You can’t connect two consoles to one mix rack. If you want two consoles you have to have 2 mix racks. You can connect the consoles via ACE (or Dante or MADI or Ethersound) using the PortB card slot.
If your show is small enough you can run monitors via a laptop (or use the console for monitors and run FoH from the laptop). To do this double patch all the pre-amps and use the first 32 channels for FoH and the second 32 for Monitors. You have to share the 8 FX engines of course. Doing Monitors on the laptop I find to be rather cumbersome but its doable.
-d