It's not so difficult to produce two md5-collided exe files

[BlackWhite]

Originally Posted by Kerlingen

You only influence the execution from an external source. If the software you're trying does not rely on an external source (and why would it ever do that?), you have no way to change the execution path, since you cannot modify any code without blowing up the hash.

Given two actual exe files say 1.exe & 2.exe, you can put them into the
combined exe's resources, and the combined exe can choose to run
1.exe or 2.exe according to the bit difference between md5_1 & md5_2,
thus the combined exe runs as if 1.exe or 2.exe is running.