\version "2.18.2"

\parallelMusic #'(voiceA voiceB voiceC)  {
  % Bar 1
  c2 c	|
  c2 c 	|
  c2 c 	|
  % Bar 2
  \parallelMusic #'(voiceD) {
    \tuplet 6/4 {
      \override TextScript.padding = #3
      c4^"this" d_"staff" e^"above" d_"last" e^"staff" f
    } |
  } 
  s1 |
  s1 |
  s1 |
}


\relative c' <<
  \new Staff = "1" { \voiceA  }
  \new Staff = "2" { \voiceB }
  \new StaffGroup <<
    \new Staff = "3" { \voiceC }
    { \skip 1
      <<
        \lyrics {
          \set alignBelowContext = #"1"
          below4 first staff
        }
        \new Staff {
          \set Staff.alignAboveContext = #"3"
          \voiceD
        }
      >> 
    }
  >>
>>