I'm looking to put together a linux firewall computer, and really the only requirement I have for it is to be able to do web trafic filtering/blocking based on user groups. IE I want to set up Group A to be able to go to website A and B but not C and have Group B be able to go to website A but not B or C. Preferably the user authentication would be something invisible to the users, even just by MAC address on the NIC would work fine. Do you guys have any thoughts on a package that could do this?