Ok, this could work. I haven't tried it by now cause of little time.

If this works there would be another requirement:

The program should be able to read regions/territories which have been created in MapPoint (so the user can decide on his own, how many countries, states or even just cities he wants to allow).

Is it possible to read this so created files and check the positions of the vehicles?

I hope, i explained it in a understandable way!