Vincent on Nostr: Yes. Add a d-tag with a uuid. That uuid corresponds to the subject of the document. ...

Yes.
Add a d-tag with a uuid. That uuid corresponds to the subject of the document.
Then create a new private key to sign the event.
Anyone you share the private key with can continue editing the document by creating new event with the same uuid and same key.
Everyone else can “fork” the document. They do it by creating a new event and using the same uuid in the d tag.