Limiting access to Cisco boces to certain users

We have numerous routers that all our NEs need access to, so that's no issue. However, there is a developer that needs full access to one particular router. I've added him to the users file, but he has access to everything right now. I've tried using huntgroups but that completely locks him out of everything. What's the best way to limit a user or users to access only particular Cisco boxes? Thanks.