A system for providing advanced voice services (AVS) in wireless communications systems includes a Real-Time Exchange (RTX) that interfaces to a wireless communications network to provide the AVS therein, wherein the AVS comprise Closed User Groups and Limiting Mobility. The Closed User Groups allow a group of users to make and receive calls only to other members of a group, and calls outside of the group are disallowed. The Limiting Mobility uses location information to restrict a mobile unit to service within one or more specified systems, cells or location areas.