first of all: Thank you for your great tool! I'm using it since years.
Here's my idea:
I record a lot of DJ mixes and listen to them. I always end up with one big mp3 file, which only contains general information about the mix, like "Promo Mix by DJ blah blah blah, October 2018". Unfortunately there's no way to include something like a playlist in mp3 tags yet. So what I would need is kind of a dynamic mp3 tag, which allows to change part of the information shown (e.g. Artist, Title), depended on a time stamp.
have a look at the ID3 standard www.id3.org
The problem would be to find a place where to store that dynamic data.
Currently, AFAIK, there is only one field, the field for synchronized lyrics (which MP3tag does not support) that looks at some kind of time stamp.
If you use it for something else than the lyrics, it would be some kind "abuse".
So I would stick to splitting tracks physically into several files and then find a player that allows to play them seamlessly. The additional information can be added to the separate files.