Hard constraint to make sure that 2 vehicles are not going to same location


How can I write a hard constraint to make sure that no 2 vehicles are going to same location? Please suggest.

for any jobs that share a same location, add a hard route constraint that all those jobs should be served by the same vehicle

Thanks @jie31best.

I was able to implement this with below approach, it is working fine but do let me know if it needs to be improved.
I am using a state updater to remember the route visiting that location -

stateManager.putProblemState(stateManager.createStateId(service.getLocation().getId()), VehicleRoute.class, route);

and wrote below route constraint -

public boolean fulfilled(JobInsertionContext insertionContext) {
	VehicleRoute route = null;
	Service service = (Service) insertionContext.getJob();
	try {
		route = stateManager.getProblemState(stateManager.createStateId(service.getLocation().getId()), VehicleRoute.class);
	} catch (Exception e) {
		//Nothing to do
	if (route == null) return true;
	String visitingVehicle = route.getVehicle().getId();
	String currentVehicle = insertionContext.getNewVehicle().getId();
	return visitingVehicle.equals(currentVehicle);