A communications system and method provide a seamless switch from a first session to a plurality of multicast sessions. A server transmits data over both a first session and alternatingly between a plurality of synchronized multicast sessions. At predetermined time intervals, the server stops transmitting data over the currently active multicast session and starts transmitting over an idle multicast session. The server is further responsive to a request to stop transmitting the data over the first session at a time when the server alternates transmission between the multicast sessions. The time intervals are advantageously sufficient to allow a receiver to join an idle multicast channel and to send a request to stop the data transmission over the first session.