I will try and solve this by adding an optional NullVoice to my part generator.
What I was hoping for before was : \groupBook #(groupPart `( ,(vocalPartCombinePart 'choirSA 'choirSoprano 'choirAlto choirSopranoVxSA choirAltoVxSA choirSopranoLyricsSA choirAltoLyricsSA structure '((inAGroup . #t))) ,(nullLyricsPart 'SA-TB choirCommonNullMusic choirCommonNullLyrics structure) ,(vocalPartCombinePart 'choirTB 'choirTenor 'choirBass choirTenorVxTB choirBassVxTB choirTenorLyricsTB choirBassLyricsTB structure '((inAGroup . #t))) ) 'choirSA-TB '((choirStaff . #t))) "choeur-SA-TB" choirSA-TB I could add this flag '((inAGroup . #t) (extraNullLyrics . #t)) and supply the music to the function. Thank you very much Jean, Carl, and David (& al. obviously). Your help and insights means everything to this list. -- Pierre-Luc Gauthier