how do I give only certain machines internet

Hi there peeps, I am curently looking into broadband for our company but was wondering how to make it so that only 5 or so machines out of 10 can access the internet. this is because all of the machines are networked to a sales system wich uses a web bassed gui + all of the machines are also linked to a file server where we keep our work, docs and stuff. we want to keep the internet away from these two servers and be able to get it on 5 of the 10 machines, any ideas?

If youre getting a dsl line, I know most routers can prevent inet access based on MAC/IP's. As far as cable internet goes, that might be a different thing though.

Are you using static or DHCP for the IP addresses? With such a small configuration, you could simply setup static IP's, and simply don't put the gateway address in for the ones you don't want to give internet access to.