Connecting Multiple Xbox 360s to the Internet w/ Linksys Router?

I will describe how my house network is setup in detail:

First in my roommate's bedroom we have a Time Warner Cable Modem, from the modem a cable runs to a Linksys BEFSR41 Wired router. Two cords come off the router down to the basement which is home to his Desktop Computer and Xbox 360. Back to the router...one more cord comes off and crosses through the wall to my bedroom and goes into a 5-port Switch. From the switch a cable goes to my Xbox 360 and another cable comes of the switch and passes through another wall and into my laptop. This is the entire home network and all the devices that need connection to the internet.

Now currently the settings on my Router are as followed:

MTU is set 1364 (this supposed to cutdown on the lag)

UpnP is Enabled.

Port Triggering is set to Trigger 4 different port ranges 53, 80, 88, 3074.

I have tried to Port Forward my Xbox, but then his had trouble connecting to Multiplayer for Madden 2010, this is where the trouble first reared its ugly head.

I understand the problem is with NAT being Open on only one Xbox and Strict on the other.

Is there is a way to have both Open? and If not is their a way to have mine as at least Moderate and his Open as he plays more Online Matchmaking then I do.

I understand DMZ Host might be something that needs to be enabled, but I'm not sure. Should one Xbox be Port Forwarded and the other DMZ?

Should nothing be enabled accept Upnp? What do I do?

I understand UPnP should allow 2 Xbox 360s to both have Open NAT, but I dont understand why this isn't the case. Maybe there is a Firmware for Linksys BEFSR41 that needs to be downloaded and applied to the router to allow the UPnP to function properly, and If I enable UPnP and nothing else (port forwarding, DMZ, triggering ,etc) will everything work?

Any help from a technical support person would be greatly appreciated.

Thanks in adbance for any help, you don't know how much of a headache you will be alleviating.

:)