Using TMG to prevent non windows domain users from accessing internet

Hello!

I'm using Windows server 2008 and use it to run my company's Domain and I have a copy of TMG Server 2010

My question is if I installed the TMG on the my Domain server can I use it to prevent internet access for Non-Domain computers, and how it is done, I've looked around the internet but I couldn't find a way to do it so I thought I should ask here...

Basically can TMG stop non-domain computers from accessing the internet ?

thank you!