where members can register and only the registered can view certain galleries and you can have special usergroups that can see sections only allowed by specific usergroups.
I have modified the core files and added functions to allow users to be assigned to a certain Collection. They can then add albums and upload only to their collections.
The admin can add users and assign what collections that they have access too.
The admin has full access to all the collections and albums still.
Problem, I did this and have to try and document what changes that were done and how to make sense to others that are not php and mysql savy.
It might take a little time to create this.
Let me know, if this is what you are looking for?
I will consider to create a install and modification procedure.