Sorry, guys, busy day. Yes, we actually have 3 XBOXes, a wii and a PS3. At any one time, 3 could be on but only one will be playing multiplayer (me).
OK, so I can put 0-65535? That's what I was wondering.
ETA: OK, cool, I set it up exactly as Chris has it listed but with my own PS3's IP address.
Thanks, dudes! I have my XBOX as 1st priority and the PS3 as 2nd. They will never be on at the same time, but I do stream Netflix to either one or the other.