The main thing you have to remember is that you have to have a router that is intelligent enough to know when one of your routes to the internet is down. This is the key. As Mooglej suggested, this could be accomplished with the help of your ISPs (if they are small enough to care This may be costly even if they are willing to do a special setup for you, but frankly, most common providers won't even have the capability to provide an OSPF setup like that using standard DSL installed equipment. They'd need to have some expensive hardware at your home that terminates each of your even more expensive connections (think T1, if you know what I mean).



You should look into setting up a PC specifically for routing, using something like m0n0wall or pfsense. You'll need to set up this router between your game machines and your multiple ISP connections. The router needs to have code running to keep track of which routes are up, and you'll be good to go.