Conceptual models organize the data as well as the processes from a business domain using a human-readable, yet formal representation language. For static data models, various modeling approaches have been proposed to represent complex multilevel abstraction hierarchies. For process models, though, current modeling approaches do not provide a flexible and powerful formalism for representing complex multilevel abstraction hierarchies. In this paper, we motivate the need for multilevel business process models, present our initial approach, and sketch future research in this area.