tx, the only problem with that is that you need a network, not everybody has one. From the sound of his question I thought perhaps he had one computer with internet access (probably because if he had his own then this wouldn't be a problem).
Also I wanted to keep this internal, Sparda's suggestion of using the NAT is probably the best for quick set up, anything requiring ports will have to be run on the host machines, but those services arn't likely to be affected by the software.