A networked virtual environment (NVE) is a computer-generated virtual world where multiple users (nodes) can assume virtual representatives (or avatars) to concurrently interact with each other via networked links. Recently, several researches utilize peer-to-peer (P2P) architecture as the foundation of NVEs to increase the scalability. In this paper, we focus on enhancing neighborship consistency for P2P NVEs, which is defined to be the ratio of the number of known neighbors to the number of actual neighbors within a node's area of interest (AOI). We address two factors that affect neighborship consistency for NVEs using Voronoi-based Overlay Network (VON). We propose mechanisms of the adaptive AOI buffer and the critical node detection to reduce the negative impacts of the two factors. We also perforin simulation experiments to demonstrate the effects of the two factors before and after adopting the proposed mechanisms.