Designating roles for specific group

Hi to all,
I have a problem designating some roles or groups in my application,
We have 10 Groups, each groups have 5 teams, each team has process that distinct to all Groups (50 process). I want is to create a role-based authentication here, so user, team leads, managers and admin should be the roles. BUT the problem is, we don't want to access the group to other groups meaning it only displays what is the appropriate page for their group.
Can you give me some idea how can I handle this? I currently use MVC3.
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