In previous results, most existing Byzantine Agreement (BA) protocols are designed for pure wired or pure wireless networks. In practice, most current networks are combined wired and wireless environments. In this paper, we extend the BA problem over combined wired/wireless network, consisting of both powerful computing processor and low-power mobile processor. Furthermore, the communication overhead of the BA protocol is inherently large because the BA protocol requires numerous rounds to exchange messages. Secure group communications over a combined wired/wireless network is very important. The protocols proposed in this paper use the hierarchical model concept to reduce the communication overhead and provide secure group communications well suited for combined wired/wireless networks.