Play two audio files in different output devices

Hi guys, I really need help with this problem.
I have a computer with a sound card and the built-in sound output. If I manually change in “settings” the output, everything works perfectly.
But when I try to do something like this mpg123 -m device 0 sample.mp3 doesn’t work at all.
I already tried with vlc and I can manually change the output by the GUI, but not by terminal commands.
Many thanks!