We want to restrict being able to enroute to an activity unless it is in the 1st pending position

Summary:

There are times that a technician needs to be able to change the order of their route. We are implementing a process to capture a reason when the technician reorders their route by using the Reschedule button. Before the technician can reschedule the activity, they are required to complete a form that collects the reason for the reschedule. However, since they can Enroute to any activity on their route, they can circumvent being required to provide the reschedule reason. Does anyone know how we can enforce that the only activity that can be "Enrouted" to is the activity in the