Send keystrokes to only one window of an application with multiple open windows or to only specific desktop?

I would like to have multiple windows of the same game open and use my mouse to trigger a macro only one one of the specific instances of that application. Now, I run them all on different desktops so I can switch between them easily, so sending the keystrokes to one desktop only would work. Basically, what I'm running into is that the macro is working but it is working on every instance of the application making chat and other stuff like that impossible and forcing me to have a hotkey slot open on the other characters to make sure they're not doing something when that hotkey is pressed.

Is something like this even possible with Keyboard Maestro or am I out of luck?

Afraid so.

There's no way for Keyboard Maestro to isolate with that granularity.