I think the return to start is the original game function of the F2 key.
On my system the call to GetAsyncKeyState() intercepts the F2 key before it gets to the game. If it is activating both the allied colors and the return to start then the only fix would be changing the allied colors to a different key.
You can change the activation key with a hex editor if you want.
If you edit allied_color.w2p you should find a 0x71 byte at offset 0x00000572
This is the
virtual key code for the F2 key. You can replace this byte with a different code to change the key.
i.e. if you make that byte 0xC0 you will change it to the [`/~] tilde key (next to the [1] key).