SLI 3 Monitor Questions

How do I go from powering three monitors with their own GTX 760s to 1 monitor to being powered by 3 GTX 760s on the fly without redoing any wiring. Or, I could have one monitor being powered by 2 and one other monitor being powered by one GTX 760.

 

right click on the desktop then go to  screen resolution 

then click the tab multiple displays