TL:DR I would like to create an attachment table that uses a many-to-many relationship. Is this doable?
The scenario is that I have several parcels that have associated Record of Survey (ROS) documents. Sometimes a ROS will cover more than one parcel, and sometimes a parcel will be covered by more than one ROS. The Enable Attachments tool creates a 1-to-many relationship by default. I may be mistaken, but I believe that this means that attaching the same file to multiple features duplicates that file in the attachment table. (If it only creates an additional row in the attachment table and does not duplicate the file, I have not been able to find that in the documentation).
Is there any reason I couldn't create a Relationship Class that uses a many-to-many relationship between the feature class and a table with BLOBs for the files to reduce overall file size?