Sharing Internet Via Router To Laptops

I'm having problems with my current network setup.I have four machines that need to be networked together (with the plan to add more in the future). One of these machines, the 'host', I want acting as the 'server' which holds all the shares etc.I have a security router which the 3 machines, and a printer are plugged into (via the lan ports). The host machine is also directly plugged in to this.That router hands out IP addresses to these machines using DHCP. The problem is that, I want the internet connection to be shared to these machines through the router, via an active wireless connection on the host computer.