3 staff piano score

[Gabriel Striewe]

Dear List,

in some, especially contemporary piano literature, a piano can have more
than 2 staffs, for example three or four, usually only for the duration
of a few bars. 

I usually notate my music using \parallelMusic.

My question is: how do I achive this? I would like a third or fourth
staff to appear only during some bars, not continuously.

Example:
(Trying to use a second pair of 
"\parallelMusic" and "<< \new Staff>>",
but this doesn't work.

\parallelMusic #'(voiceA voiceB) {
  c''1|
  c'1|

  %Bar 2
  d''1|
  d'1|
}

\parallelMusic #'(voiceC voiceD voiceE) {
  %Bar 3
  e''1|
  e'1|
  c'1|
}

\score {

  \new PianoStaff \with {
    instrumentName = "Klavier"
  }
  <<
    \new Staff  {\voiceA}
    \new Staff   {\voiceB}

  >>
  <<
  \new Staff {\voiceC}
  \new Staff {\voiceD}
  \new Staff {\voiceE}
  >>
                                                                               
  \layout { }
}
                                                                                
                     
Any help would be greatly appreciated.

Regards,

Gabriel