Establishing communications in a dynamic spectrum access (DSA) network requires communicating nodes to 'rendezvous' before transmitting their data packets. Frequency hopping (FH) provides an effective method for rendezvousing without relying on a predetermined control channel. FH rendezvous protocols have mainly targeted pairwise rendezvous, using fixed (non-adaptive) FH sequences and assuming a homogeneous spectrum environment, i.e., all nodes perceive the same spectrum opportunities. In this paper, we address these limitations by developing three multicast rendezvous algorithms: AMQFH, CMQFH, and nested-CMQFH. The three algorithms are intended for asynchronous spectrum-heterogeneous DSA networks. They provide different tradeoffs between speed and robustness to node compromise. We use the uniform k-arbiter and the Chinese remainder theorem (CRT) quorum systems to design our multicast rendezvous algorithms. We also design two 'optimal' channel ordering mechanisms for channel sensing and assignment, one for AMQFH and the other for CMQFH and nested-CMQFH. Finally, we develop a proactive out-of-band sensing based dynamic FH (DFH) algorithm for online adaptation of the FH sequences used in the proposed rendezvous algorithms. Extensive simulations are used to evaluate our algorithms.