Usergroups based on where user posts
 

Hi,

I was wondering if there is a way I can set a usergroupe to user based on where he posts. So let's say I have forum about sport, and let say it's divided in 4 sub forums: football, tennis, basketball and athletics. So if a user have lets say 4000 posts on forum, but most of them are in football (let's say 80% of them), I would like to put him in usergroup "football". So when I have some important news from football world, I whant to send mail to thous people, that are in football usergroup.