Ok, I've been poking around this for a while but I cant figure out a way to get it to work.
Here's the situation:
My college apartment has multiple wired connections. Upstairs, I have a wrt54gl running openwrt with a static wan ip address connecting to our schools internet connections. I use it to host a couple servers and miscellaneous things. Downstairs, we have another network that we use mainly for gaming, general internet access, etc that has a dynamic wan address also connecting to the schools network, that one has a wrt54g v6 so no 3rd party firmware. What I'd like to do is wirelessly connect the two networks, while still allowing them to have their own wan connections. More or less if i just ran a cable from one of the lan ports on the downstairs router to one of the lan ports on the upstairs router. However I haven't found a way to do this. WDS doesn't seem to me like it'd help since it just rebroadcasts the signal from one router out to a wider area, which, I don't think, is what I want.

Any help would be appreciated.