A customer can office all over the world. Based on how the territory are divided they can be covered by different personnels in sales, accounting etc. Won’t it make more sense to define territory in the Address rather than in Customer? It will make possible to auto fill the territory based on the Billing or Shipping address . Chances of mistake happening in selecting the correct territory will be less. Permission can be given based on the territory based on which basis the Users can see the Address, Contact, Quotation,Sales Orders, Invoices etc.