In this paper we present a flow handoff scheme and network architecture to support group mobility in a wireless ad hoc network. Because a wireless ad hoc network does not have a fixed backbone network and the mobile base station moves randomly, the conventional handoff scheme can not efficiently predict group mobility and is not feasible to support a burst handoff traffic occurring due to group mobility. In this paper, we propose a new flow handoff scheme to support this problem. In the proposed handoff scheme, we use hello message extended of AODV routing protocol to predict group mobility and remote information to support a burst handoff call traffic occurring due to group mobility. An analytical Markov model is developed for the proposed scheme and the numerical results discussed. The performance of the proposed scheme is compared to the other conventional handoff scheme.