Integrating business processes across disparate systems of partner organizations is known to be one of the biggest challenges facing enterprise systems development. Recent developments in service technologies and advanced middleware solutions, together with efforts toward standard interfaces, have helped overcome some of the difficulties. However, managing the rules that govern the interactions between cross-organizational business processes is still under developed. In this chapter, we present an approach for enterprise integration facilitated through a rule based messaging technology. In particular, we will present insights into rule specification, verification, and execution for such an enterprise integration architecture.