A radio communication system includes provider equipment and at least two subscriber radio units, each operable in a telephone communication mode and a dispatch communication mode. The provider equipment is operable to receive a communication request from a subscriber radio unit, the request including a requested communication mode and a mode-specific identifier identifying a target subscriber radio unit. The provider equipment compares the mode-specific identifier to the requested communication mode. If the mode-specific identifier does not match the requested communication mode, the provider equipment searches a provided database containing at least two mode-specific identifiers for each subscriber unit and, using the received mode-specific identifier, reads the mode-specific identifier matching the requested communication mode and, using the mode-specific identifier matching the requested communication mode, sets up communication between the originating subscriber radio unit and the target subscriber radio unit in the requested communication mode. As an alternative to the provider equipment cross-referencing a telephone number identifier from its database in response to a received private access identifier, a protocol to communicate data over voice channel can be used to query the phone number identifier directly from the target subscriber unit itself.