4 Monitors, 2 or 3 used for gaming - what setup?

What graphics card setup would be recommended for a 4 monitor setup, where 3 monitors would be used for gaming (the other would just be a desktop extension).

I am trying to form a setup where I can run games simultaneously on a single monitor each, preferably at max settings. My minimum setup would be, 2 gaming monitors, 2 display monitors. I am not interested in gaming across monitors, where game appears on both monitors.

All monitors would be 1080p, 24inches.