In Creo 2.0 it is possible to create different assembly situations by using multiple placement sets. These placements can be controlled by a new parameter (PTC_CONSTRAINT_SET). If there is an extra column showing this parameter in the model tree it can be changed very quickly there.
The idea is to control these combinations of placement sets inside the view manager (like layers, styles, orientations ...). In this case it can be used inside the combination states. When switching through the combined states the prepared assembly situations can be switched pretty easy.