Does enyone konw how to configurate squid.. to block all internet pages. Exept 2 or 3 that I want to leave unblocked..

The gool is to make an easy point where pople can read news from only two or three sithes (lets say max 6 or 7)..

I have allready insalled r-kisok plugin for mozila, and remower all menues and toolbars and insalled squid.. i have cinfigurated the mozila to start (on full sreen.kiosk mode) every time the user is loged on.. There wil be no keyboard.. only mouse.
but i dont now hove to configureate it to work like i want..

Is there any other way to do that??? meybe with IPtabels or something???