Pc Engine CD Rom: How to output cd audio (music) separately

Hi, well everything is in the title.

I noticed on some games of Cd Rom / Super Cd Rom, the sound effects are much higher than the music itself.
I'm looking for a way to output RGB from the Core Grafx or IFU (both are RGB modded) and sound from the Jack output on the CD Rom 2, in one single cable.
That way you could control the volume of the music only, from the Cd Rom 2.

Is that possible?