Primary and secondary group permissions
 

I have some sub-forums for dealers to post news.

I created a group for dealers in the UK to be able to publish news in the UK sub-forum only. Only that group has permissions to post in that sub-forum.

I did the same thing for the USA.

So far so good. I manually make special accounts for dealers with UK or USA as the primary user group so they can post in their respective countries' sub-forum.

I now have however the need to allow for an international dealer to be able post both in the UK and the USA forums. With UK as the primary group and USA as an additional group in that user's account, they are still only able to post on the UK forum. How can i make it so they can post in both forums by adding additional secondary groups to the user's account? Of course i could create a UK/USA group, but i have more countries and the whole thing would be very complicated very easily.

?I hope i made myself clear!