Switch screen between 3 nvidia GPUs

I have a small wotkstation with 3 GPUs 1 GTX 750 Ti 2 GTX 760 Ubuntu 14.04.2

i have Samsung screen it works on GPU-0 according to Nvidia-Settings which is GTX 760

my problem is how to force the screen to work on GPU-1 which is GTX 750 Ti

how to switch the screen between nvidia cards