wasapi – Create a gstreamer sink that appears in the list of audio devices on Windows

I would like to write a gstreamer pipeline that mixes the audio from two sources. I then want to be able to select an audio source from an app on my computer, i.e. Discord, such that the mixed audio will play as if it was coming from my mic.

It seems simple enough to get the mixing right, but it seems like I need to use something like Virtual Audio Cable to achieve the second part. Is there a way to do this entirely in gstreamer or with something more lightweight than installing Virtual Audio Cable?