I'm working on some hymns and noticed that I need to add square brackets just above the treble clef to indicate the introductory part of the hymn (usually performed by an organ or orchestra before the choir sings).
As an example, I can show a sheet of music from the hymnal of The Church of Jesus Christ of Latter-day Saints:
https://media.ldscdn.org/pdf/music/hymns/2001-01-1000-nearer-my-god-to-thee-eng.pdfI tried using \startGroup and \stopGroup, but this creates a long slash through every bar, which is not ideal (I believe this one is for analysis purposes).
I searched for the snippets, but I didn't find anything like that.