\paper {
    ragged-right = ##f
    ragged-bottom = ##f
    ragged-last-bottom = ##f
  }

\new Score {
  \new StaffGroup 
  <<
    \new Staff \relative c, { \clef "bass" g1\f c'1 }
    \new Staff \relative c' { \clef "bass" c1 c,1 }
    \new Staff \relative c { \clef "bass" c1 c1 }
  >>    
}
\pageBreak

\new Score \with
{
  \override VerticalAlignment #'max-stretch = #8
}
  \new StaffGroup 
  <<
    \new Staff \relative c, { \clef "bass" g1\f c'1 }
    \new Staff \relative c' { \clef "bass" c1 c,1 }
    \new Staff \relative c { \clef "bass" c1 c1 }
  >>    
}