\version "2.13.11"

guitar = \relative c' {

  % Monophony
  c4 d e f |

  %% Temporary polyphony
  <<
    {
      \voiceOne
      c4 d e f |
    }
    \tag #'temp-voice {
      \new Voice {
        \voiceTwo
        c,1 |
      }
    }

    \tag #'temp-tabvoice {
      \new TabVoice {
        \voiceTwo
        c1 |
      }
    }
  >>

  % Back to monophony
  \oneVoice
  c'4 d e f |

}

\score {
  \new StaffGroup <<
    \new Staff {
      \clef "G_8"
      \keepWithTag #'temp-voice
      \removeWithTag #'temp-tabvoice
      \guitar
    }
    \new TabStaff {
      \keepWithTag #'temp-tabvoice
      \removeWithTag #'temp-voice
      \guitar
    }
  >>
}