Attaching lyrics to intermittent vocals with polyphony

[Christopher R. Maden]

tl;dr: interrupted five-voice polyphony — how to attach lyrics, and 
still get proper polyphonic engraving, in 2.18.2?

I had a call-and-response arrangement with three response parts, and 
assigned lyrics to the responses like so:

  <<
    {
      \new Voice = "response"
      s1*6 |
    }
    {
      <<
        \context Voice = "resp_hi" {
          \voiceOne \transpose c c' { \autoBeamOff \melRespOne }
        }
        \context Voice = "harmony" {
          \voiceThree \autoBeamOff \harmRespOne
        }
        \context Voice = "response" {
          \voiceTwo \autoBeamOff \melRespOne
        }
      >>
      % ...
    }
  >>
  \context Lyrics = "response" {
    \lyricsto "response" {
      \respOne
    }
  }

This produced nicely-stemmed notes for the responses, and allowed me to 
attached lyrics across disparate polyphonic response sections.

However, I added two more responses, and voices past \VoiceFour are 
unrecognized.  When I use the default << \\ >> polyphony, the \context 
approach no longer works.  Using the built-in voice "1" (etc.) works 
when there’s only one uninterrupted instance of polyphony; however, it 
doesn’t carry across a break.  If I try to set \context on a voice, I 
get a single (chord-ish) note column, plus the warning:

Preprocessing graphical objects...
test.ly:22:3: warning: ignoring too many clashing note columns

(although the lyrics do work).

What’s the optimal approach here?

Three MWEs are attached: one with the old, working approach; the second 
with default polyphony and unaligned lyrics; the last with an attempt at 
Voice context, which generates an error.

Thanks,
crism
--
Chris Maden, text nerd
<URL: http://crism.maden.org/ >
Emperor Norton had the right idea.

polyphonic_lyrics_3.ly
Description: Text Data

polyphonic_lyrics_5_default.ly
Description: Text Data

polyphonic_lyrics_5_context.ly
Description: Text Data