Is it possible to effectively use multiple displays?

I am running `ai2thor` on an EC2 instance that has 8 GPUs. I have an `Xorg` process running on each GPU but if I start multiple `ai2thor` processes (eg: either by instantiating two different `ai2thor Controller`s within a single python process or by running 2 python processes, each of which starts an `ai2thor Controller`, I notice that all the THOR Unity processes end up on display 0. I think it would be possible for me to run more THOR processes on my machine if I could force them to use different GPUs. Is this a reasonable assumption? If it is, is it possible to pass some argument to `Controller.start` to force the THOR Unity processes to use different GPUs?