redfish36117

We have a small book store and have installed a wireless router for our customers use. But I have two computers on that router that are wired and I need these to be behind a firewall or something so that the files cannot be seen. I read somewhere about using another wired router and connecting it to the wireless router. Then connecting the two wired pc to it and that would keep them from being seen. Does this sound right? Any help would be greatly appreciated.