'hideNotes' from midi or align lyrics differently

[Jay Anderson]

I'm working on some hymns and have a standard outline which aligns
lyrics to the "soprano" voice. I just ran into one which begins with
the basses alone. Ideally I'd like to use \set associatedVoice =
"bass", but this unfortunately has to be set one syllable early which
isn't an option at the beginning. As an alternative I did this in the
soprano voice just for alignment:

  <<
    {
      \hideNotes
      c4 c c |
      c2 c4 |
      c2 c4 |
      c2. |
      \unHideNotes
    }
    R2.*4 |
  >>

But these notes show up in the midi output. Is there a way to
temporarily mute midi for a voice? (also shouldn't 'hideNotes' also
hide them from midi?). As a final workaround I put the same notes from
the bass in the soprano voice so the midi sounds correct (this creates
other things to worry about like having to hide slurs). Is there a
cleaner alternative?

To sum up:
- Is there a way to use \set associatedVoice "bass" at the beginning?
- Is there a way to mute a voice temporarily?

-----Jay