This sounds more interesting! I haven't played with the users table yet. Would it be possible using your method for admins to create groups of users on their own and then assign files to them?

The database only exists on a test server behind my firewall right now, but it will be used for mortgage transaction tracking. With each mortgage, there are realtors, lawyers, borrowers, etc., who should be able to view the file. For instance, one office of realtors should be able to see all the transactions they are involved with, whereas a borrower may only be able to see his or her own mortgage.

Thanks again for your ideas!