well, I grounded the PCs together using some speaker wire. this made the vetra much more stable except that the UPS hated it. The first power spike and 3 of the 4 PCs shutdown instead of being protected like they have always been in the past.

sigh....
I can't live without the UPS because the power sucks here and the vetra doesn't work if I use them.
I get power spikes 3-4 times a week here.