An ad hoc network is formed by a group of mobile hosts communicating over wireless channels. Such a network operates without any fixed network interaction and centralized administration. For the network environment is highly dynamic, the established routing paths are so fragile to maintain stable communication, especially the connection-oriented communications are quite difficult to be maintained. In our approach, the network infrastructure is initiall3y constructed by several communication groups, which are called Dynamic Group Infrastructure. This paper proposes the group-level connection maintenance based on Dynamic Group Infrastructure to implement connection-oriented routing. Our approach enhances the routing robustness of connection-oriented communications. The simulation results show that this routing approach under such construction outperforms the previous works in message complexity for connection-oriented communications.