Limit Access to one specific wireless network based on username

We have 6 laptops that teenagers use in a building that has multiple wireless networks.  The teenagers use one of two different generic usernames to log onto the domain.  The wireless network we want them to use denies access to social networking, porn, violence ect.... via Opendns.  However they can access all of that stuff if they re-direct the adapter to use the "for public" wireless access that is niether secure nor denies access to the bad stuff.  What is the best way to do this?  Can I just remove the little bars link on the task bar via Group Policy Editor on the Domain Controller?  If so, how?  Is there a better way?  Thank you.