This might be off topic but hopefully of interest for the community. I had been using mt (Mediatomb) for streaming music many years until my old Ubuntu PC finally passed away. The big advantage of mt is its ability to get configured in the most flexible way, combined with a very small footprint. You could use any tag written by Picard to create several views and subviews in order to present your music to the player/renderer and even manipulate them with JavaScript beforehand. Current Linux distributions however no longer support mt since the project was left abandoned many years ago.
Fortunately the Gerbera project revived most of the mt code and is actively maintained and well documented. Some patches however didn’t make it into the current code but are most relevant to deal with ‘our’ advanced relationships. I’d like to draw your attention to my issues #758 & 759 which are flagged ‘help needed’ and deal with multiple tags and values. Maybe this old mt discussion and patch applies.
Hopefully I made you curious and have a closer look at this wonderful project. A Ubuntu PPA is available.