Run two different versions of game simultaneously?

[satandidnowrong]

Nioh, specifically.
I have 1.24.8 and 1.24.7 in respective directories.
No matter which executable is ran, the version populates from the version in a directory named Nioh.
When you run the other executable, the current running game pops to screen.

I am porting code edits/auto assembly from one to an other.
Any ideas?