Split network in Windows?

[twodayslate]

http://www.ex-parrot.com/~pete/upside-down-ternet.html
I would like to something like the above in Windows. Does anyone know how to do that?

I know that fon (http://www.fon.com/en/) can do this but I do not want to buy a new router.

[oracleguy]

You could do it in Windows server. Instead of iptables you would use the windows routing and remote access snap-in for the MMC. That would let you do the kittens thing with ease. Squid however does run on windows, I've used it there before so you should be able to set it to the image thing too. It just might take a tad more effort.

A smoothwall (http://www.smoothwall.org) router could do it too since it supports multiple networks like that. And it already has squid and iptables on it.