Correct. That is not exactly what I am thinking. In the way wikis are implemented, each author is independently the only author of their own version of the same document, and they can each adopt edits from the various forks of that document.

I am thinking more of co-authorship of a single document. There would be a "owner" who can tag other npubs as having edit permissions, and relays would accept an update signed by any of the tagged co-authors, and the owner retains the ability to add or remove co-authors' edit rights.