There has been extensive research on data coordination in peer-to-peer(P2P) environments using event-condition-action rules. A P2P environment differs from traditional distributed systems in that it has no central control. Thus, data synchronization mechanisms such as triggers need to be revised and extended in order to be applied in P2P settings.In this thesis, we study a distributed trigger mechanism for P2P environments and propose a general method that could be used to implement it on top of any SQL3 compliant database system with trigger support. Hence, this thesis proves that it is convenient to incorporate the this mechanism into existing database systems with minimal efforts. We implement the distributed trigger on top of PostgreSQL as the P2P layer of the Hyperion architecture. Also, we discuss a loosely coupled transaction semantics and apply it to the distributed trigger mechanism.