It is partially a limitation.
Can a single grouped list be achieved? Yes 
So, why hasn’t it?
Simplicity’s sake.
By grouping, I would also need to consider how to do with:
- muted characters - only mute if all of them are muted?
- focus - if one of the followers are focused, what to do with focus colors?
- language - to contruct the travel message, I would need a more advanced syntax, such as the icu-syntax or similar, to support any type of language.
- … and probably some more things
And also, I would need to do a bit of work on the backend. Not a big deal, but still.
So, I went with the simply way and sent a travel event for each! 
But yes. We need to improve Area.
One think you should look at is my suggestion of exit icons, and especially the sentence about giving them a semantical meaning. Maybe this idea can be part of the Area navigation thoughts as well.
The Silver Crescent? A place completely unreachable? Cool!
But… yeah. I totally see your point!