This suggestion would be helped along to the realm of possibility if someone found an xenforo extension that did it. There's no option in the admin area that does this as far as I know.
I think we might need to separate the language for frontier territories versus the main region.
One concern with the current system is that it is tricky for nations not well versed in the region to know the maximum they're supposed to stop at. And that number changes daily and requires some...