This is something a microcontroller would handle. No doubt.
you'd need quite a few transmitters and recievers to! I think 8 sets in total for all. Seems impractical to make something like this, I would just by one.
making a PC-PC lan connection is complicated, to put it simply. Even conecting two PCs through a hub (wired) is complicated enough, and thats about the simplest way to do it.
Buy two wireless networking cards (PCI, prefereably) and a wireless hub/switch - with some built in privacy tools. - all in will cost about £70 odd.