Allowing Skype only in specific countries

Hello,

First of all, i know Skype is pretty clever application to go through firewalls, and to be able to reach the person you want to make the call.

What I'm looking for is to a configuration, which allows Skype connections only to the country I live, let's called country X. Connections to all the other countries should be denied. I understand that Skype can also use other clients as proxies, but in all the cases, i would like to allow the first proxy connection to be within the country I like, the country X and denying all the other connections to other countries.

I have CF2 and IDP licenses activated in USG40. 

Thank's for you help