A communication system (100) determines whether to establish a point-to-multipoint communication or a point-to-point communication for conveyance of Multimedia Broadcast Multicast Service (MBMS) data based on a number of mobile stations (MSs) (102-104), both idle mode and maintaining an active connection, serviced by the system and subscribed to an MBMS service. The system, broadcasts (306) a control message that includes an access probability factor. In order to avoid overloading the system with responses to the control message, MSs maintaining an active connection ignore (506, 508) the control message while idle mode MSs determine (506, 512) whether to respond based on the access probability factor. The system compares (310) a number of received responses to a threshold and determines whether to establish a point-to-multipoint communication (312) or a point-to-point communication (322) based on the comparison. The system also adjusts (314, 330) the access probability factor based on the number of responses.