An efficient multicast protocol is presented by using a heuristic function for passing a virtual token to decide the message total ordering. Unlike existing token-passing based algorithms, there is no physical token passing message in the protocol, instead, the token holder piggybacks token passing onto normal multicast messages. Executing the heuristic function does not incur any communication overhead and only relies on local information of a token holder. For a group of n processes and k multicast messages, the protocol is able to achieve atomicity of one message by average (n-2)/k point-to-point control messages. Dynamic membership is non-blocking, namely, each individual process in the group can take unilateral decisions at each step of the membership algorithms. System-wide consistent group configuration can be obtained in consistent order of normal multicast messages. Performance of the protocol is shown by implementation figures.