It can be tricky to build a content structure which allows users to access the appropriate documents in the back end with the current user access system of specifying a single node as the starting point for a user.

I was wondering : is it possible to intercept the event that checks authorization when attempting to edit a document (eg that returns error Authorization error: Unauthorized access to URL: )

and add my own checks (eg based on specific document ids, external user groupings etc)?