I have a use case where we want to show rows grouped by a field; so we created a group copy type relationship. We need to list out all the files name related to each row, but looks like we can't create a child off of a group copy type relationship. Is there any workaround anyone has done before so I can show this list of files for the grouped row?
A group relationship is already a combination of a table and row, which is why you can't do another another row relationship to a group. You could potentially do a table relationship that is ordered and then create a row relationship to the attachment. Alternatively it might be possible using custom code and an apex data relationship.