\version "2.18.2"

noBreak =
#(define-music-function (parser location music) (ly:music?)
  #{ \temporary\override
       Score.NonMusicalPaperColumn.line-break-permission = ##f
     #music
     \revert Score.NonMusicalPaperColumn.line-break-permission
  #})


% example:

\paper {
  ragged-right = ##f
}

musicOne = { R1*4 R1*4 }
musicTwo = { R1*4 R1*4 }
musicThree = { R1*4 R1*4 }
musicFour = { R1*4 R1*4 }

\score {
  \musicOne
}

\score {
  { \musicTwo \musicThree }
}

\score {
  \noBreak { \musicTwo \musicThree }
}

\score {
  \musicFour
}