linking 2 or 3 subnets simply!

[MADMAX7147]

I have a linksys router, dsl on the wan port, 5 or so computers wired. I also have a belkin g access point on the roof. I set my neibor up pretty much the same way, but with his own subnet. is there a way to link without disableing one or both dhcp,s and set ip's mannually and change him to my subnet?? would be cool to game without the internet, and possibly share two dsl lines.