An important issue arising from Peer-to-Peer applications is how to accurately and efficiently retrieve a set of K best matching data objects from different sources while minimizing the number of objects that have to be accessed. This paper resolves this issue by organizing peers in a Semantic Link Network Overlay, where semantic links are established to denote the semantic relationship between peers' data schemas. A query request will be routed to appropriate peers according to the semantic link type and a lower bound of rank function. Optimization strategies are proposed to reduce the total amount of data transmitted. Categories and Subject Descriptors H.2.4 [Database Management]: Systems ? query processing; H.3.3 [Information Storage and Retrieval]: Information Search and Retrieval ? retrieval models, search process, selection process. General Terms: Algorithms, Design, Management.