Anybody who uses Dynamo runs into this problem at some point, Editing Groups.
I’m talking about adding elements to groups, changing family types, changing builtin instance parameters that can not be changed to “can vary by group instance” like Unconnected height or Base Constraint.
these are all not posible right now.
Ungrouping and Regrouping is not an option because of all the Attached Detail Groups, Dimensions and other Annotations that would be lost.
So please upvote this Idea to add group editing to the Revit API, and lets hope it makes it to the Revit Public Roadmap.
As you probably know, some of those limitations can be overcome when there is only 1 group instance… So you can swap all the others off to a temporary type, edit 1 and swap them back. Not ideal but gives an option. I did a graph long ago, none of the nodes will work, but it gives an idea…