How to direct the audio stream from different applications to different stars. cards?

Question

linux

Let's say 2 audio players and 2 audio cards are installed, the stream from each player goes to a certain sound. map.

Answer 1

And it depends on what your sound subsystem is running (which in turn depends on what kind of Linux you have there ;-) ).
You can have audio running OSS (very old, but some perverts use it), ALSA, and the PulseAudio audio server.
If PulseAudio works for you, then there should be no problems with solving your question.
See about settings in Skype and microphones - there is about microphones, but you will have something similar.

Answer 2

pavucontrol