Okay, I'm 99% on this but since I've never done it myself and I'm not a hardcore network guru so I leave the 1% caveate in case there is something I don't know regarding your particular unit or some oddness in the new line of "gaming adapters".
A gaming adapter is just a network bridge (before marketing got hold of them they were all called wireless network bridges). You can use a standard switch behind the gaming adapter to connect multiple ethernet components and allow them network access all at once (no need to switch over between them, you can have tons of pieces connected - just watch your bandwidth while gaming).
So each console or unit requiring ethernet would plug into the switch and then one of the ports on the switch would be connected to the bridge/gaming adapter which provides wireless connectivity to your wireless network (specifically router and whatever else you have on it).
As for switches, you won't need gigabit so get whatever you want. I have a very very cheap one in my media cabinet that I got for free, there are always deals on switches (heck you can even use a router with multiple ports on the back because that's just a built in switch just don't connect the WAN). Just make sure your adapter is configured properly before putting the switch in the middle. Should be a 5 second no brainer, cheap and expandable.
Here's a netgear with some rebates: http://www.compusa.com/products/prod...ct_code=294498