Many group key agreement protocols (GKA) for secure group communication (SGC) based on the Diffie-Hellman key exchange principle have been proposed in literature. All of these protocols require member serialization and/or existence of a central entity. In this paper, we propose a simple group Diffie-Hellman key agreement protocol which removes these two limitations. Moreover, the new protocol needs minimum (two) rounds of rekeying process and efficiently support high dynamics.