How to only record sound from specific window

[Ian]

I was trying to record some gameplay today with only the game noise and no commentary. I turned off microphone recording and I selected the "Game" mode on Action, assuming that it would only record audio from the game that was being recorded. However, I was on a Discord call with some friends and their voices got recorded. I know this might be a stupid question, but I Google searched everywhere and cannot for the life of me find an answer. Can someone please explain how to do this?

[Piotr]

No software has a feature like that.