hjk101 said If not friend, why friend shaped?,@electrineer that is not the problem. The problem is separation and a switch for multiple versions of the app (both actual versions as different platforms). Is it account level. Geo IP level or even both. 
If the platform already supported displaying a regional error message (which is quite likely) and there are already tools in place to identify regional traffic it would indeed be fairly easy.
If not it's a lot harder. Especially if you need to block US accounts not just IP/ISP based traffic origin.,What an elaborate way to say that sugar is bad for you!```