Adding video with extra audio track to vlc playlist from sh?

Question

VLC

Need to add video files with additional audio tracks to vlc playlist.
From the GUI, everything works fine, but only for a single file, not a directory. So, I tried to run from the console.
The loop calls vlc with a parameter for the extra track.

vlc "$VIDEO" --input-slave "$SOUND" --playlist-enqueue --one-instance &

If vlc is already open, then --input-slave is generally ignored.
If vlc is not already running, then the first video file plays correctly with the added audio track, but then --input-slave is again ignored and the following video files are still played with the first audio track.
Is it possible to specify the parameters differently, so that it would work with additional audio tracks?
Or other video players where additional audio tracks are automatically connected.
So far, you have to run one file at a time, without a playlist, and close the player each time.