It is possible to refine access to the Types of Entries a User can create, the Elements a User can view and the specific Entries a User can view and update.
User group limitations don't apply to Users with the User Type Manager.
Limit Access to Types Put a Type into specific User Groups to limit access of that Type to those specific User Groups.
Limit Access to specific Elements Put an Element into specific User Groups to limit access of that Element to Users within those specific User Groups.
Limit Access to specific Entries Create an Entry Group and link that Entry Group to a specific User Group. Whenever an Entry is placed into that specific Entry Group, it will only become viewable to Users within that User Group. This method can be used to create specific editorial review communities.