Narrated custom slideshows that autoplay audio narration

I’m looking for ideas for ways to create a single Impress document containing several custom slideshows (for various subsets of the slides) that will sequentially show each slide in the selected custom slideshow subset while playing that slide’s audio narration track and automatically move to the next slide (all the way to the end of the custom slideshow).

I’ve come close to achieving that by making use of
Slide Transition/Modify Transition/Sound/Other sound…
to select an mp3 narration audio file for each slide and setting the Duration to a slightly longer play time.

Unfortunately, this approach seems to require that all the audio files remain external to the Impress file which then makes it difficult to simply email the presentation to anyone.

Possible solution # 1: Make audio files already attached/embedded in the slide or elsewhere in Impress file available for selection from:
Slide Transition/Modify Transition/Sound/Other sound…

Possible solution # 2: Provide options for autoplaying an audio file included on a slide AND once the audio file finishes, provide a way to move to the next slide in whichever custom slideshow was selected. The advantage of this solution is that it might be able to be engineered to work for embedded video clips as well.

I apologize if I’ve somehow missed an obvious solution to get narrated slideshows to play through on their own.

It would be acceptable to have to have separate Impress files for each custom slideshow.

Use the menu Slide Show > Custom Slide Show.
Click New in the Dialog.

110549110549 HB NewSS

Specify the slides to be included, enter a name and click OK.

Thank you!
Your reply will no doubt help others better than I would have if I had tried to describe how I was already generating multiple custom slide shows from a single (email-able) Impress file.
It’s great to be able to have one file multiple self narrating slideshows (some short, some long) that can play through on their own once selected.
The only problem is that the audio files for slide-transitions seem to have to be emailed as separate files that must be present in the same directory as the Impress file is stored to in order to play the custom slide shows.

I would have thought that self narrating (and email-able) slideshows would be a popular capability.

Thank you for your response.