adding empty staves in the middle?

[Molly Preston]

Hi. I was wondering if anyone knows how to add empty staves to a score in
the middle. I realize this may not be possible and my best option is to use
the following wherever I want to add staves:
<<
    \new Staff {
      \once \omit Staff.TimeSignature
      s1*5
      }
  >>

I have two voices and a piano, but my teacher wanted me to add empty staves
in the middle for corrections. He wanted two systems on a page with two
empty staves in the middle. If I use the above in the left hand of the
piano part it just extends the piano bracket over it. I wasn't sure if
there was another way.

girl = {
R1*4
}
croc = {
R1*4
}
up = {
a4 b c d
}
down = {
<<
    \new Staff {
      \once \omit Staff.TimeSignature
      s1*5
      }
  >>
fis4 fis fis fis
}

\score {
<<
 \new Staff <<
     \new Voice  = "girl" { \autoBeamOn \girl \accidentalStyle
modern-voice-cautionary }

         >>
        \new Staff <<
           \new Voice = "croc"  { \autoBeamOn \croc \accidentalStyle
modern-voice-cautionary }

         >>


    \new PianoStaff  <<
     \set PianoStaff.instrumentName = #"Piano"
     \new Staff = "up" {  \up \autoBeamOff }
      \new Staff =  "down" { \down }

    >>
>>
}


I hope this makes sense and I'm sorry if my code is screwed up. I took
stuff out so it was easier to read and understand what I was attempting.

-Molly