Background audio

Is it possible to completely disable the BG audio (I have music as BG) for certain slides but not others.  I know I can lower audio on slides with voiceover audio, but that's not what I want to do.  My preference is to "turn off" audio on slide 1, and then later on a slide in the middle of the project, and then back on through the end.  Second option is to start BG audio on second slide and run continuously through to the end.  The project is self-paced, so it's not an option for me to manually turn down the track for specific slides, because it will likely be at a different time for every learner.  Are either of these options possible?

Hopefully this question makes sense.  The only videos I found are those that show how to import BG audio and then edit audio track, but they only showed it for all slides in project, so I fear what I want to do is not (yet) possible - if not, hopefully in future iterations (ahem.) 

Thanks for any advice!