A device (102) external to a wireless communication system infrastructure (104), defines (402) a dispatch group having a dispatch group identifier and including a plurality of wireless units (300). The device receives (404) a call for the dispatch group, the call including a message. The device establishes (408), through the wireless communication system infrastructure, a group connection to the plurality of wireless units in response to receiving the call; and delivers (410) the message and the dispatch group identifier to the plurality of wireless units through the group connection.