&SC1=Chatter (Enables File Attachments to log to Chatter)
If you wish to override the default behavior where files are saved on the Chatter Feed for the master object, you may use the AttachmentParentId parameter to identify the record on which the file should be posted. You may set AttachmentParentId to a User Id, Group ID or record Id.
Parameters
AssembleChatterallows multiple files to be attached to a single Chatter post.
ChatterCommunityIdspecifies the Chatter Community receiving an output file attachment.