Integrated fiber-wireless (FiWi) access networks provide a powerful platform to improve the throughput of peer-to-peer communication by enabling traffic to be sent from the source wireless client to an ingress optical network unit (ONU), then to the egress ONU close to the destination wireless client, and finally delivered to the destination wireless client. Such wireless-optical-wireless communication mode introduced by FiWi access networks can reduce the interference in wireless subnetwork, thus improving network throughput. With the support for direct inter-ONU communication in the optical subnetwork, throughput of peer-to-peer communication in a FiWi access network can be further improved. In this paper, we propose a novel hybrid wavelength division multiplexed/time division multiplexed passive optical network (WDM/TDM PON) architecture supporting direct inter-ONU communication, a corresponding decentralized dynamic bandwidth allocation (DBA) protocol for inter-ONU communication and an algorithm to dynamically select egress ONU. The complexity of the proposed architecture is analyzed and compared with other alternatives, and the efficiency of the proposed system is validated by the simulations.