[CentOS] UPS question

so I have a bunch of servers at work that are on DUAL UPS's (1 per each of 2 power supplies). Its mostly HP gear, but also some Sun and IBM. Ideally I'd like the system to not go into shutdown unless BOTH UPS's that a particular box is plugged into (there's actually 4 UPS, 2 per each of 2 racks). Has anyone ever configured anything like that with NUT or whatever?

Right now, I'm running without any UPS monitoring software, as the whole building is on a generator that comes on 60 seconds after a power failure, so my 7kVA(!) UPS's don't see much use, and also I just installled these new racks and UPS's and haven't really had the time to sit down and figure it all out.