diff --git a/src/cli.rs b/src/cli.rs
index 2cae383..87585e1 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -1,7 +1,6 @@
 use clap::{Parser, Subcommand};
 
 use crate::commands::asset::AssetArgs;
-use crate::commands::group::GroupArgs;
 use crate::commands::upload::UploadArgs;
 
 #[derive(Parser, Debug)]
@@ -23,7 +22,6 @@ pub struct Cli {
 #[derive(Subcommand, Debug)]
 pub enum Command {
     Asset(AssetArgs),
-    Group(GroupArgs),
     Upload(UploadArgs),
 }
 
diff --git a/src/commands/group/list.rs b/src/commands/group/list.rs
deleted file mode 100644
index a11c491..0000000
--- a/src/commands/group/list.rs
+++ /dev/null
@@ -1,60 +0,0 @@
-use clap::Args;
-use tellers_api_client::apis::accepts_api_key_api as api;
-
-use crate::commands::api_config;
-use crate::output;
-
-#[derive(Args, Debug)]
-pub struct ListArgs {
-    #[arg(long, env = "TELLERS_API_KEY")]
-    pub api_key: Option<String>,
-
-    #[arg(long, env = "TELLERS_AUTH_BEARER")]
-    pub auth_bearer: Option<String>,
-}
-
-pub fn run(args: ListArgs) -> Result<(), String> {
-    let cfg = api_config::create_config();
-    let api_key = api_config::get_api_key(args.api_key)?;
-    let bearer_header = api_config::get_bearer_header(args.auth_bearer);
-
-    tokio::runtime::Runtime::new()
-        .map_err(|e| format!("failed to start runtime: {}", e))?
-        .block_on(async move {
-            let groups = api::list_groups_group_list_get(
-                &cfg,
-                Some(&api_key),
-                bearer_header.as_deref(),
-            )
-            .await
-            .map_err(|e| {
-                let mut m = format!("failed to list groups: {}", e);
-                match &e {
-                    tellers_api_client::apis::Error::Reqwest(req_err) => {
-                        if let Some(status) = req_err.status() {
-                            m.push_str(&format!("; http_status: {}", status));
-                        }
-                    }
-                    tellers_api_client::apis::Error::ResponseError(resp) => {
-                        m.push_str(&format!("; http_status: {}", resp.status));
-                        if !resp.content.is_empty() {
-                            m.push_str(&format!("; response_body: {}", resp.content));
-                        }
-                    }
-                    _ => {}
-                }
-                m
-            })?;
-
-            output::info(format!("Retrieved {} group(s)", groups.len()));
-
-            if groups.is_empty() {
-                output::info("No groups found");
-            } else {
-                println!("{}", serde_json::to_string_pretty(&groups).unwrap_or_default());
-            }
-
-            Ok(())
-        })
-}
-
diff --git a/src/commands/group/mod.rs b/src/commands/group/mod.rs
deleted file mode 100644
index 1ebe163..0000000
--- a/src/commands/group/mod.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-use clap::{Args, Subcommand};
-
-mod list;
-
-pub use list::{run as list_run, ListArgs};
-
-#[derive(Args, Debug)]
-pub struct GroupArgs {
-    #[command(subcommand)]
-    pub command: GroupCommand,
-}
-
-#[derive(Subcommand, Debug)]
-pub enum GroupCommand {
-    List(ListArgs),
-}
-
diff --git a/src/commands/mod.rs b/src/commands/mod.rs
index c033d54..18b7ee7 100644
--- a/src/commands/mod.rs
+++ b/src/commands/mod.rs
@@ -1,5 +1,4 @@
 pub mod api_config;
 pub mod asset;
-pub mod group;
 pub mod prompt;
 pub mod upload;
diff --git a/src/commands/upload/main.rs b/src/commands/upload/main.rs
index f371ed9..a9d562e 100644
--- a/src/commands/upload/main.rs
+++ b/src/commands/upload/main.rs
@@ -393,6 +393,7 @@ fn run_upload(args: UploadCmdArgs) -> Result<(), String> {
     }
 
     let mut requests: Vec<AssetUploadRequest> = Vec::with_capacity(files_to_upload.len());
+    let mut related_umids_per_file: Vec<Vec<String>> = Vec::with_capacity(files_to_upload.len());
     let mut file_upload_ids: Vec<String> = Vec::with_capacity(files_to_upload.len());
     let mut file_in_app_paths: Vec<String> = Vec::with_capacity(files_to_upload.len());
     let mut upload_paths: Vec<PathBuf> = Vec::with_capacity(files_to_upload.len());
@@ -445,14 +446,18 @@ fn run_upload(args: UploadCmdArgs) -> Result<(), String> {
             vec![],
         );
 
-        if let Some(metadata) = umid {
-            if let Some(umid_value) = metadata.material_package_umid {
-                source_info.capture_device_umid = Some(Some(umid_value));
+        if let Some(metadata) = umid.as_ref() {
+            if let Some(umid_value) = metadata.material_package_umid.as_ref() {
+                source_info.capture_device_umid = Some(Some(umid_value.clone()));
             }
-            if let Some(first_umid) = metadata.file_package_umids.first() {
-                source_info.umid = Some(Some(first_umid.clone()));
+            if let Some(first_with_data) = metadata.file_package_umids.iter().find(|u| u.has_data) {
+                source_info.umid = Some(Some(first_with_data.umid.clone()));
             }
         }
+        related_umids_per_file.push(
+            umid.map(|m| m.file_package_umids.iter().map(|u| u.umid.clone()).collect())
+                .unwrap_or_default(),
+        );
 
         let req = AssetUploadRequest::new(
             i32::try_from(content_length).unwrap_or(i32::MAX),
@@ -515,6 +520,13 @@ fn run_upload(args: UploadCmdArgs) -> Result<(), String> {
             );
             preproc_req.generate_time_based_media_description =
                 Some(!args.disable_description_generation);
+            let all_related_umids: Vec<String> = related_umids_per_file
+                .into_iter()
+                .flat_map(|v| v.into_iter())
+                .collect();
+            if !all_related_umids.is_empty() {
+                preproc_req.related_umid_for_master_clip = Some(Some(all_related_umids));
+            }
             let _ = progress_handle.add_info(format!(
                 "Triggering preprocessing for {} asset(s)...",
                 preproc_req.assets.len()
@@ -744,6 +756,7 @@ fn run_two_queue_pipeline(
 
         let consumer = async move {
             let mut completed_responses: Vec<AssetUploadResponse> = Vec::new();
+            let mut completed_related_umids: Vec<Vec<String>> = Vec::new();
             while let Some(file_info) = upload_rx.recv().await {
                 progress_handle.decrement_upload_queued();
                 progress_handle.pop_upload_pending();
@@ -755,11 +768,12 @@ fn run_two_queue_pipeline(
                     .to_string();
                 progress_handle.set_upload_current(Some(file_name.clone()));
 
-                let (req, _upload_id, in_app_path_str) = build_single_upload_request(
-                    &file_info,
-                    &base_dir_async,
-                    &in_app_path,
-                )?;
+                let (req, _upload_id, in_app_path_str, file_related_umids) =
+                    build_single_upload_request(
+                        &file_info,
+                        &base_dir_async,
+                        &in_app_path,
+                    )?;
                 let responses =
                     request_presigned_urls(&cfg, &vec![req], &api_key, bearer_header).await?;
                 let upload_resp = responses
@@ -799,6 +813,7 @@ fn run_two_queue_pipeline(
                     ));
                 }
                 completed_responses.push(upload_resp);
+                completed_related_umids.push(file_related_umids);
                 progress_handle.set_upload_current(None::<&str>);
                 progress_handle.set_upload_current_pct(None);
             }
@@ -810,6 +825,13 @@ fn run_two_queue_pipeline(
                 );
                 preproc_req.generate_time_based_media_description =
                     Some(!disable_description_generation);
+                let all_related_umids: Vec<String> = completed_related_umids
+                    .iter()
+                    .flat_map(|v| v.iter().cloned())
+                    .collect();
+                if !all_related_umids.is_empty() {
+                    preproc_req.related_umid_for_master_clip = Some(Some(all_related_umids));
+                }
                 let _ = progress_handle.add_info("Triggering preprocessing...");
                 let preproc_tasks = api::process_assets_users_assets_preprocess_post(
                     &cfg,
@@ -847,7 +869,7 @@ fn build_single_upload_request(
     file_info: &FileToUpload,
     base_dir: &PathBuf,
     in_app_path: &Option<String>,
-) -> Result<(AssetUploadRequest, String, String), String> {
+) -> Result<(AssetUploadRequest, String, String, Vec<String>), String> {
     let content_length = std::fs::metadata(&file_info.upload_path)
         .map_err(|e| format!("failed to stat {}: {}", file_info.upload_path.display(), e))?
         .len();
@@ -877,12 +899,16 @@ fn build_single_upload_request(
         None,
         vec![],
     );
+    let related_umids: Vec<String> = umid
+        .as_ref()
+        .map(|m| m.file_package_umids.iter().map(|u| u.umid.clone()).collect())
+        .unwrap_or_default();
     if let Some(metadata) = umid {
         if let Some(umid_value) = metadata.material_package_umid {
             source_info.capture_device_umid = Some(Some(umid_value));
         }
-        if let Some(first_umid) = metadata.file_package_umids.first() {
-            source_info.umid = Some(Some(first_umid.clone()));
+        if let Some(first_with_data) = metadata.file_package_umids.iter().find(|u| u.has_data) {
+            source_info.umid = Some(Some(first_with_data.umid.clone()));
         }
     }
     let req = AssetUploadRequest::new(
@@ -890,7 +916,7 @@ fn build_single_upload_request(
         upload_id.clone(),
         source_info,
     );
-    Ok((req, upload_id, file_in_app_path))
+    Ok((req, upload_id, file_in_app_path, related_umids))
 }
 
 async fn request_presigned_urls(
diff --git a/src/main.rs b/src/main.rs
index 60a4d75..15c8619 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -27,16 +27,6 @@ fn main() {
                 }
             }
         }
-        Some(cli::Command::Group(group_args)) => {
-            match group_args.command {
-                commands::group::GroupCommand::List(list_args) => {
-                    if let Err(error) = commands::group::list_run(list_args) {
-                        eprintln!("error: {}", error);
-                        std::process::exit(1);
-                    }
-                }
-            }
-        }
         Some(cli::Command::Upload(upload_args)) => {
             if let Err(error) = commands::upload::run(upload_args) {
                 eprintln!("error: {}", error);
diff --git a/src/media/metadata.rs b/src/media/metadata.rs
index 9cc1480..4970694 100644
--- a/src/media/metadata.rs
+++ b/src/media/metadata.rs
@@ -4,9 +4,18 @@ use std::path::PathBuf;
 use std::process::Command;
 use std::sync::OnceLock;
 
+/// A file-package UMID with a flag indicating whether the stream has media data.
+#[derive(Clone, Debug)]
+pub struct FilePackageUmid {
+    pub umid: String,
+    /// True if this UMID came from a stream with actual media data (video/audio);
+    /// false if from a stream with `codec_type == "data"` (no media data in the stream).
+    pub has_data: bool,
+}
+
 pub struct MediaMetadata {
     pub material_package_umid: Option<String>,
-    pub file_package_umids: Vec<String>,
+    pub file_package_umids: Vec<FilePackageUmid>,
 }
 
 pub fn extract_media_metadata(path: &PathBuf) -> Result<MediaMetadata, String> {
@@ -21,7 +30,7 @@ pub fn extract_media_metadata(path: &PathBuf) -> Result<MediaMetadata, String> {
 #[derive(Debug, Default)]
 pub struct MxfUmids {
     pub material_package_umid: Option<String>,
-    pub file_package_umids: Vec<String>,
+    pub file_package_umids: Vec<FilePackageUmid>,
 }
 
 fn run_ffprobe_json(path: &PathBuf) -> Result<Option<Value>, String> {
@@ -98,7 +107,7 @@ fn extract_mxf_umids(path: &PathBuf) -> Result<MxfUmids, String> {
     };
 
     let mut material = None;
-    let mut file_package_ids: Vec<String> = Vec::new();
+    let mut file_package_ids: Vec<FilePackageUmid> = Vec::new();
 
     if let Some(format) = payload.get("format") {
         if let Some(tags) = format.get("tags") {
@@ -113,22 +122,23 @@ fn extract_mxf_umids(path: &PathBuf) -> Result<MxfUmids, String> {
     if let Some(streams) = payload.get("streams") {
         if let Some(streams_array) = streams.as_array() {
             for stream in streams_array {
-                // Skip streams with codec_type "data"
-                // codec_type == "data" means that there is no data in the stream
-                if let Some(codec_type) = stream.get("codec_type") {
-                    if let Some(codec_type_str) = codec_type.as_str() {
-                        if codec_type_str == "data" {
-                            continue;
-                        }
-                    }
-                }
-
+                // Collect file_package_umid from all streams (including codec_type "data")
+                // so they can be sent as related_umid_for_master_clip. Record whether
+                // the stream has media data (video/audio) or is data-only (codec_type "data").
+                let has_data = stream
+                    .get("codec_type")
+                    .and_then(|v| v.as_str())
+                    .map(|s| s != "data")
+                    .unwrap_or(true);
                 if let Some(tags) = stream.get("tags") {
                     if let Some(tags_obj) = tags.as_object() {
                         if let Some(umid_value) = tags_obj.get("file_package_umid") {
                             if let Some(file_umid) = sanitize_umid(umid_value.as_str()) {
-                                if !file_package_ids.contains(&file_umid) {
-                                    file_package_ids.push(file_umid);
+                                if !file_package_ids.iter().any(|u| u.umid == file_umid) {
+                                    file_package_ids.push(FilePackageUmid {
+                                        umid: file_umid,
+                                        has_data,
+                                    });
                                 }
                             }
                         }
diff --git a/src/tellers_api/openapi.tellers_public_api.yaml b/src/tellers_api/openapi.tellers_public_api.yaml
index 33c87e0..a588380 100644
--- a/src/tellers_api/openapi.tellers_public_api.yaml
+++ b/src/tellers_api/openapi.tellers_public_api.yaml
@@ -878,212 +878,6 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/HTTPValidationError'
-  /group/create:
-    post:
-      tags:
-      - accepts-api-key
-      summary: Create Group
-      operationId: create_group_group_create_post
-      parameters:
-      - name: x-api-key
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: X-Api-Key
-      - name: authorization
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: Authorization
-      requestBody:
-        required: true
-        content:
-          application/json:
-            schema:
-              $ref: '#/components/schemas/CreateGroupRequest'
-      responses:
-        '200':
-          description: Successful Response
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/CreateGroupResponse'
-        '422':
-          description: Validation Error
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/HTTPValidationError'
-  /group/list:
-    get:
-      tags:
-      - accepts-api-key
-      summary: List Groups
-      operationId: list_groups_group_list_get
-      parameters:
-      - name: x-api-key
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: X-Api-Key
-      - name: authorization
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: Authorization
-      responses:
-        '200':
-          description: Successful Response
-          content:
-            application/json:
-              schema:
-                type: array
-                items:
-                  $ref: '#/components/schemas/GroupResponse'
-                title: Response List Groups Group List Get
-        '422':
-          description: Validation Error
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/HTTPValidationError'
-  /group/update:
-    post:
-      tags:
-      - accepts-api-key
-      summary: Update Group
-      operationId: update_group_group_update_post
-      parameters:
-      - name: x-api-key
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: X-Api-Key
-      - name: authorization
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: Authorization
-      requestBody:
-        required: true
-        content:
-          application/json:
-            schema:
-              $ref: '#/components/schemas/UpdateGroupRequest'
-      responses:
-        '200':
-          description: Successful Response
-          content:
-            application/json:
-              schema: {}
-        '422':
-          description: Validation Error
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/HTTPValidationError'
-  /group/users/add:
-    post:
-      tags:
-      - accepts-api-key
-      summary: Add Group Users
-      operationId: add_group_users_group_users_add_post
-      parameters:
-      - name: x-api-key
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: X-Api-Key
-      - name: authorization
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: Authorization
-      requestBody:
-        required: true
-        content:
-          application/json:
-            schema:
-              $ref: '#/components/schemas/GroupUsersRequest'
-      responses:
-        '200':
-          description: Successful Response
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/GroupUsersResponse'
-        '422':
-          description: Validation Error
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/HTTPValidationError'
-  /group/users/remove:
-    post:
-      tags:
-      - accepts-api-key
-      summary: Remove Group Users
-      operationId: remove_group_users_group_users_remove_post
-      parameters:
-      - name: x-api-key
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: X-Api-Key
-      - name: authorization
-        in: header
-        required: false
-        schema:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: Authorization
-      requestBody:
-        required: true
-        content:
-          application/json:
-            schema:
-              $ref: '#/components/schemas/GroupUsersRemoveRequest'
-      responses:
-        '200':
-          description: Successful Response
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/GroupUsersResponse'
-        '422':
-          description: Validation Error
-          content:
-            application/json:
-              schema:
-                $ref: '#/components/schemas/HTTPValidationError'
 components:
   schemas:
     AgentMessageRequest:
@@ -1406,24 +1200,6 @@ components:
       required:
       - path
       title: CreateFolderResponse
-    CreateGroupRequest:
-      properties:
-        name:
-          type: string
-          title: Name
-      type: object
-      required:
-      - name
-      title: CreateGroupRequest
-    CreateGroupResponse:
-      properties:
-        id:
-          type: string
-          title: Id
-      type: object
-      required:
-      - id
-      title: CreateGroupResponse
     FileReference:
       properties:
         file_name:
@@ -1472,88 +1248,6 @@ components:
       - entity
       - teller_config
       title: FileType
-    GroupResponse:
-      properties:
-        id:
-          type: string
-          title: Id
-        name:
-          type: string
-          title: Name
-      type: object
-      required:
-      - id
-      - name
-      title: GroupResponse
-    GroupRights:
-      type: string
-      enum:
-      - ADMIN
-      - READ
-      - WRITE
-      title: GroupRights
-    GroupUsersRemoveRequest:
-      properties:
-        group_id:
-          type: string
-          title: Group Id
-        user_ids:
-          items:
-            type: string
-          type: array
-          title: User Ids
-          default: []
-        emails:
-          items:
-            type: string
-          type: array
-          title: Emails
-          default: []
-      type: object
-      required:
-      - group_id
-      title: GroupUsersRemoveRequest
-    GroupUsersRequest:
-      properties:
-        group_id:
-          type: string
-          title: Group Id
-        user_ids:
-          items:
-            type: string
-          type: array
-          title: User Ids
-          default: []
-        emails:
-          items:
-            type: string
-          type: array
-          title: Emails
-          default: []
-        right:
-          $ref: '#/components/schemas/GroupRights'
-          default: READ
-      type: object
-      required:
-      - group_id
-      title: GroupUsersRequest
-    GroupUsersResponse:
-      properties:
-        user_ids:
-          items:
-            type: string
-          type: array
-          title: User Ids
-        not_found:
-          items:
-            type: string
-          type: array
-          title: Not Found
-      type: object
-      required:
-      - user_ids
-      - not_found
-      title: GroupUsersResponse
     HTTPValidationError:
       properties:
         detail:
@@ -1634,6 +1328,13 @@ components:
             type: array
           - type: 'null'
           title: Override Entity Ids
+        related_umid_for_master_clip:
+          anyOf:
+          - items:
+              type: string
+            type: array
+          - type: 'null'
+          title: Related Umid For Master Clip
       type: object
       required:
       - assets
@@ -1812,25 +1513,6 @@ components:
       - ended_at
       - error_message
       title: TaskResponse
-    UpdateGroupRequest:
-      properties:
-        group_id:
-          type: string
-          title: Group Id
-        name:
-          anyOf:
-          - type: string
-          - type: 'null'
-          title: Name
-        is_public_read_access:
-          anyOf:
-          - type: boolean
-          - type: 'null'
-          title: Is Public Read Access
-      type: object
-      required:
-      - group_id
-      title: UpdateGroupRequest
     UseAgentToolRequest:
       properties:
         tool_id: