Registration nation chooses usergroup automatic

[Triple-X]

I would like to have a possibility that the users choose their nation when they sign up to the board and is put in usergroups that are set up for their nation.

For example, my board is currently all norwegian, but my community will be starting a international part now, and we want the users from other countrys then norway to only see a international part which can be done by usergroups, but since we will have alot of new members this will be alot of work if it can't be done automatic...

someone plz help, its urgent