You can use Trustee privileges to limit access to different types of records.  Trustee Privileges can be set for Comment Categories, Report Manager, Contact Type, Collateral, Loan Groups, Loan Portfolios, Status Codes, Transaction codes, Work Packet Templates, Work Queues, and Task Templates.  Only users added to the Trustee list on the left side of the screen will be able to view the record type that is being configured.  The bottom window will house the privilege check boxes that control the specific abilities of the Trustees.