1. A system comprising: a design tool that is operable to display a first process model and a second process model, each including a progression of task nodes, coordinator nodes that coordinate the progression of the task nodes, and event-flow activities that transfer control between the first process model and the second process model; and a control flow assignment system that is operable to merge the first process model and the second process model to obtain a merged process model, and further operable to insert control flow coordinators within the merged process model, based on locations of the event-flow activities within the merged process model.