Model-driven middleware support for team-oriented process management. Management of collaborative processes involving multiple parties is one of the dominant topics in contemporary information system research. While the process perspective is quite well understood and supported by a wide range of modeling approaches, it is necessary to go beyond the process perspective alone. We specifically address the following question: If we consider the involved parties of a collaborative process as a team, then (1) which are the general formation rules for such a team together with the collaborative process it carries out and (2) to which concrete underlying organizational structure do these rules apply? To address this question, we present the organizational modeling approach Sonar. The accompanying models are rather high-level and illustrative but at the same time they are rich enough in order to generate executable models and other kinds of code that together form the core of a middleware implementation for team-oriented process management.