Rather than using a router you can use a network switch instead. you can get different sizes depending on how may pc's you want to connect to it. There is an example one here http://www.ebuyer.com/52760-netgear-prosafe-gs105-5-port-gigabit-switch-gs105 they are straight forward to install, just connect the switch to your Virgin hub in one of the 4 output sockets and then connect your pc's to the switch. They should all work then, if not restart hub switch and pc's and they will then be assigned an IP address.
The first example is a GB switch, if your pc's are all 10/100/1000 compatable and you are using the 100MB Virgin service you will get full speed on all pc's. If not you can get a cheaper switch which is 10/100 http://www.ebuyer.com/8894-netgear-prosafe-fs105-5-port-10-100-compact-switch-fs105