Any way to limit bandwidth used by network pc's?
 

My mate has a home network, with around 5 pc's connected to it wirelessly.

Now, three of these pc's are used for MMORPG's just about 24/7, and whenever I try to play any online games with him, his ping is skyhigh. In fact, everyone on the network has crappy lag and ping.

Now I suggested that this might be because his upload cap is getting hit, lagging the entire line speed (his upload cap is around 40kbs). Would this be right?

If so, is there any way to limit how much upload bandwidth each pc can use, so that in total, say, only 35kbs is ever used, as not to throttle the entire line?

He can probably set something up in his router. I use a Linksys router flashed with HyperWRT 2.1b1 + Thibor15c, and it can be done in Applications & Gaming > QoS.