To decrease search time in P2P network, there have been many researches on overlay construction, specifically by clustering peers into semantic groups. Although environment may change dynamically over time, the process of clustering is predetermined and static in most of these researches and doesn't address issues related to dynamic solution concepts. This leads to undesired increase of network traffic. We model the problem as a non-superadditive coalition game and a distributed dynamic coalition formation algorithm through myopic best-reply rule with farsighted strategy is suggested. Through the proposed algorithm, peers with similar interests that are also closer to each other in the underlying physical network form coalitions. Finally the stability of overlay using core solution concept is studied. This approach leads to speeding up lookup and subsequently decreasing the number of query messages in the network.