As far as I can tell it's software that allows you to play phone/tablet apps fullscreen on your computer. Typically if a program is forced true fullscreen the computer will limit the number of instances to 1 visible, and any number in the background. Emulators of this sort probably already include the ability to emulate multiple apps at a time, so I'm not sure why you would be required to run more than one instance. If the software uses a frameless/borderless window to produce the fullscreen effect and has no measure included to directly forbid multiple instances, then you should be able to run it several times and I'm about 99% sure any of the multiboxing software available would be able to handle/force window resizing so you could view them all at once.

Honestly though we would need some more information in order to help with any more than generalizations...

Thanks,
Bettysue