In a small PAN, devices are typically connected together over wireless or wired link layer technology and communication between devices is point-to-point or point-to-multipoint. In this paper, we discuss some common methods to negotiate unicast and multicast keys on MAC layer. We also present an upper layer group key management framework to facilitate flexible and secure group communication in a PAN. Our main observation is that the current MAC layer security solutions do not support well multicast communications. For improved efficiency, we propose to enhance the MAC layer security solutions with a multiparty handshake procedure.