you can't do that with a simple linksys

if the packet is sent to another network, it is being forwarded to the gateway

I just have enough free time these days :)
and forums are pretty good for keeping me up to date on the new trends in IT (I also am in linuxquestions.org, kadets.info,...

what are you trying to do exactly?

one wifi router
one wifi nic

internet-modem-wifirouter--
-cable--one PC
~~wireless~~second PC you bought the NIC for
~~wireless~~laptop with built in wifi nic

level-1 routers do not disconnect you for having too many connections. but I'd keep emule connections below 254 anyhow

actually, level-one is the best cheap-type router family I've ever dealt...