I've already had a working solution with 2 objects.
But if there are more (infinite instances), I could not figure out picking the right object instances in c2. With the IID's only, it is not easy choose which one of the "colliders" should react somehow if a collision is recognized - for example simply stop pathwalking, and continue when the "other" instance is outside of the collision range again.
Maybe someone here has an idea of creating such an event.