Sessions + logging in from only one location

[eluser]elverion[/eluser]
I've already got all the code in place to handle users logging in and out using CI sessions and inserting all session data into the database. Now, I want to be able to forcefully log out (just remove the userdata section) any other sessions using that same user ID. I think this would help to improve the security.

Thing is, I'm not entirely sure how I should go about doing this. What do you recommend?