As I just discover @Code-Jack’s reference to the discussion about having a generic LIST layout that could embrace both collections and sets, I think the “SELF” Filter suggested above and elsewhere could help there a lot, because a collection could probably be seen as basically a Set of all objects that shall belong to this collection.
The difference to the suggested “SELF” object would probably just be that the suggested “SELF” object would relate to the “host” page itself, rather than to a particular LIST, Set or Collection on that page.