Lightweight Chapter Markers to Organize Narrative Threads

My project braids multiple narrative threads together.

Within a single folder, the chapters alternate between these threads.

For example: Chapter 1 follows Thread X, Chapter 2 follows Thread Y, Chapters 3 and 4 return to X, Chapter 5 goes back to Y, and so on.

To keep it straight, I’ve been stuffing the chapter titles with reminders about which thread each one belongs to and what happens in it. That sort of works, but it’s clumsy. A cleaner system would be the ability to add a small tag, icon, or color marker to individual documents so I can see at a glance which thread they belong to. (These markers could be used for any purpose, but my use case is thread organization.)

One drawback is potential UI clutter. So the question is whether we’re willing to tolerate a little extra visual noise in exchange for better organization. Thoughts?