Second GPU Disabled when installing nVidia Driver on Ubuntu 18.04

  1. I have two GeForce GT 710 cards in my PC, running Ubuntu 18..04 standard install (GDM / Gnome Desktop)
  2. To each I have connected one monitor via HDMI and second monitor via DVI
  3. Two monitors connected to one card and two to the other card - A total of four (4) monitors
  4. As soon as I install the nVidia driver, the two monitors connected to the second card do not work, show up as disabled in the nVidia Settings
  5. The Displays in the Gnome Settings show only the two monitors connected to the first card.
  6. If I don't install the nVidia driver, all is well - all monitors show up and work normally
  7. When I enable the disabled monitors in the nVidia Settings, it forces me to create a new X Display
  8. When I do, the monitors stay on, black background, the Gnome session dosn't start on them.

Please tell me how to set up 4 monitors on Ubuntu 18.04 / GDM / Gnome Shell 3.26!