There is a demand in the Public Protection and Disaster Relief (PPDR) community for high bandwidth services on mobile devices. Group communication is an important aspect of PPDR networks. In IP based networks multicast is the preferred method to efficiently transmit data to more than one receiver simultaneously. It is important PPDR users can switch seamlessly between wireless networks. This paper describes improvements to multicast in Fast handovers for Proxy Mobile IPv6 (PFMIPv6) to provide seamless mobility to its users. We also identify and explore the specific problems stemming from difference in end-to-end delay between the old and new path during handovers for multicast traffic. A novel mechanism to determine the delay difference between two paths in a PFMIPv6 system is described and an implementation of this system is evaluated. It is shown the proposed approach can prevent multicast packet loss during a handover.