The following case describes a universe of research project management. The university has many research groups that belong to different departments. Researchers belong to exactly one research group. Projects are decomposed into Work Packages (WP), and each WP has exactly one research group assigned to it as WP leader. To execute a research project, researchers need to be assigned to Work Packages. 
A researcher can be assigned to any WP, independent of which RG is leading the WP. 
However, “service delivery” from one group to another needs to be traceable. It should be possible to have an overview of researchers from other groups working on WPs led by a RG. This “service delivery” implies that whenever a researcher changes research group, the current assignments as team member of a WP are terminated and new ones are created to keep a correct record of the service delivery. Likewise, if WP leadership is re-assigned, team member assignments are re-recorded to ensure correct recording of the service delivery.