Hello! I am working on a new site which has somewhat unique access control restriction requirements; and I'm trying to figure out if using this component/system is the answer to the problem:

The site itself is not complicated at all; but it's divided into sections that are maintained by different "departments". There are 5 departments, each with 2 'Management' level users that have access to the Back-End Administrator section. There is 1 overall Site Admin.

In the Category Manager, I have created a root Category for each Department. This gives me the ability to restrict page creation for each manager to their own departments (granted, they can still see all of the other categories in the list, but they cannot modify them).

What I need to be able to do now, though, is pass this same type of granularity to Menus and Modules. For instance, now, the Manager for Department A can go into the Module Manager and edit the Menu module for his sidebar menu. Because All of the menus are listed in the display area, he can potentially assign it to a page that doesn't belong to his Department. Similarly, he could create a new module and assign it to a page that doesn't belong to his department.

Is this a case for using Multi-Site installs? Should each department have its own joomla site/installation that is governed by a core install? Or will the Master/Slave setup handle this?