I may need to know more specifics on what you're trying to measure. If you have a number of endpoints, and are trying to find out which are connected together, then you could use a PXI DMM and switch module(s) to perform an opens and shorts test. If you are additionally attempting to drive the mechanical relays with the same PXI system, then you could also use the 64-channel PXI-2567 relay driver module. With external power, it can output a maximum drive voltage of 50 V, maximum drive current of 600 mA/channel, up to 25 A per module.
NI PXI-2567 Product Page
Hope this helps!
Switch Product Support Engineer
NI - USA