Text property for bracket
I learned in the German forum that there is no way to rotate a font by -90 °. This is often used in polyphonic music in old scores to name the choruses; example see attachment (CAPELLA I, CAPELLA II, CHORUS I...).
A general solution for all texts may be difficult for the 'automatic placement' and also useless, since I can think of no other application for vertical texts.
However, it might not be so difficult to provide a text property for the bracket used to group choral voices, with the text automatically placed vertically to the left of the bracket, as in the example.