tri-montor set-up help requested

Hello everyone,

I wasn't sure what section to put this in - hardware or software, but here it goes.

My workplace is in the middle of a new system upgrade and we just aquired 5 HP Z600 Workstations running XP and dual Xeon X5560 processors and dual nVidia Quadro NVS 295 video cards.

One of the Z600's has a unique display setup that I am hoping someone here can help with. The issue is we are currently using 2 - 22 inch Wide Screen Monitors (HP's LP2275w's) and one 30 inch monitor (HP's LP3065).

I have the two 22's resolution set to 1680 by 1050 pixels and they look great. However, when I try to crank up the resolution beyond 1280 x 800 pixels on the 30 inch monitor, something weird happens.

When the resolution is set higher than 1280 x 800, when you move the mouse to the edge of the 30inch's screen - the screen "scrolls" and then finally kicks over to the next monitor over.

Anyone know how to turn off this "scrolling" so we can bump up the resolution on the 30 inch display?

BTW - this is for a security desk, the two 22's we use for our access control software, outlook, and reports. The 30 inch monitor is for our new digital video surveilance software to monitor cameras (hence the upgrade).