Found a promising software solution, called
Indie VolumeAllows you to selectively choose where to output sound from any program, to any audio output. This should allow me to direct the sounds from my jukebox program to my audio card, while keeping the rest of my sounds focused on the touchscreen's speakers, right in front of the user.
Here's what I envision: a hidden 'admin' button which serves as a windows hotkey for switching between apps running on my touchscreen. In the arcade, I can walk up to my touchscreen, hit the hidden admin button, and the screen will switch to my jukebox application, allowing me to change songs or do whatever. Then, hit the button again, and I'm back into SimpleTouch FE, my touchscreen front end.
All the jukebox audio will output to a separate audio card, serving my arcade room's speaker system. The rest of the touchscreen's audio will broadcast on the forward mounted speakers on the touchscreen, plugged into the onboard audio. This way, someone can be playing touchscreen games while the jukebox is playing.