Weakly organized structure of Peer-to-Peer systems may cause severe data management problems and high communication overheads. We partially resolve these problems by developing a novel semantic approach to efficiently create, search and organize data objects in E-Commerce Peer-to-Peer applications. The approach is based on the notion of Unspecified Ontology (UNSO). Unlike many existing systems using a global predefined ontology, UNSO approach assumes that the ontology is not fully defined, leaving some parts of it to be dynamically specified by the users. The data objects inserted to the system organize a multi-layered hypercube graph topology, providing a stable infrastructure for efficient semantic search and routing operations. The proposed method has a potential of becoming a practical infrastructure for Peerto-Peer data management applications.