Instrument group feature suggestion

Hi all! This feature suggestion is something that's been bugging me about musescore, but also essentially all other notation softwares too. That is, the lack of flexibility and customisation when it comes to instrument labels. Quite a lengthy post, so I'll give an outline here. First I'll give the motivation for the feature, then an explanation for what the solution I'm suggesting is, and finally a walk through of a design I made. I should add that I'm not a programmer or familiar with the musescore infrastructure; it could be that this is too fundamental a change and so can't really be implemented, but yeah!

Motivation:
Right now, staff labels are directly attached to the instrument. But this isn't always best. For example, it is common to have the word "Flute" in between the two flute staves in a full score. Also, when a percussionist is dealing with multiple instruments simultaneously it is useful to have both the player number and instrument names shown (see Behind Bars, p.272). Of course as with many things it is possible to do this all by hand. But, with multiple labels per system, over a large scale orchestral score? This adds up, not to mention that manual adjustments of text labels become messed with if any other spacing/formatting change is required. I would love there to be a way to create such labels that are attached to several staves.

Feature description:
I suggest adding a notion of "instrument groups". This would be a collection of instruments that are semantically grouped together as a unit (not to be confused with bracketed instrument groupings). An instrument group would not be able to contain other groups, and would have its own full and abbreviated label. This label could be given formatting options. These would include:
- whether it should always stay to the left of any instrument groups, or whether it should go between them.
- an option to display the label with text perpendicular, with an optional bracket.
- padding space for the instrument names.

And of course it would have its own text style option.

With an odd number of staves the label should go inline with the instrument name on the middle staff, as opposed to optically centred. With an even number of staves, the label should be optically centred between the middle two staves. This algorithm should be the same as the one for a single instrument with many staves.

An additional bonus of this is that a group with a single staff has the group label aligned with the instrument name. Imagining an example with two flutes, it would be possible to set the abbreviated names for the flutes as "1" and "2", and the group name as "Flute". Then, when one of the staves is hidden when empty, the visible staff would essentially have the label "Flute 1"! This is very elegant in my opinion.

Design:
In the instrument menu, there is a 'Group' button next to the 'Add' button.
Clicking this button while instruments are selected groups the instruments into a new group. The instrument menu tree model works great for this!

The settings option can be used to customise the appearance and name of the group.

The following are ways in which the label could be displayed.

For me this would be hugely beneficial as it would solve a LOT of pains I have, especially as I'm writing and engraving percussion ensemble and orchestral pieces. Also, it frees the constraint of staves needing to correspond strictly to an instrument, which is useful in extended notation where an additional staff can be used to show changes in an expressive variable (the lachenmann violin clef is an example). I'd be really interested in what y'all have to say about this feature/design, whether it is doable or too structurally intensive, and whether it is something actually needed.

Thanks, Valérie.