\score { \new ChoirStaff << \score_pre \transpose c \pitch_a \new Staff << \Mad \Bd >> \lyricsto Vad \Lad \transpose c \pitch_b \new Staff \Mbd \lyricsto Vbd \Lbd \transpose c \pitch_c \new Staff \Mcd \lyricsto Vcd \Lcd >> \layout { \context { \Voice \consists "Ambitus_engraver" } } }