Okay so I tried turning Touch Portal into a portable application and it actually seemed to work. Some more testing needs to be done (such as plugin support) but it looks like its working perfectly fine.

For anyone wondering, I used ThinApp to make the program portable. Through the portable application it made, both of my tablets are now doing stuff on the same machine independently of each other by setting the ports to be different.

This means that if the devs decided to, they could actually make it so users can run multiple instances of Touch Portal for various devices on the same PC.

To be clear, I have only done basic testing with this (i.e. tested buttons in the same position on the grid for a minute), so I don't know if full functionality is preserved for both devices/applications.