Abstract: The present invention provides a method for determining an authorization for a call based on an Originating Station Number (OSN) in a Primary Rate Interface (PRI) in a virtual private network (VPN) customized dialing plan. A new access type is defined enabling first authorization levels to be assigned at the level of the OSN. A service logic database at a Service Control Point stores second authorization level required to complete the call. A combination of a Switch ID (SwID) of the Service Switch Point (SSP) through which the call is being made and the Trunk Group Number (TGN) of the Private Branch Exchange (PBX) along with the OSN or range of OSNs serves as a primary key to the database. The first authorization level is compared to the second authorization level required to proceed with a call, and an action is selected based on the results of the comparison.