Setting the width of system-starter curly braces

[Siska Ádám]

Dear List,


I have four horns playing in an orchestra like this:

  \new GrandStaff <<
    \set GrandStaff.instrumentName = #"Corni"
    \set GrandStaff.shortInstrumentName = #"Cor."
    \new Staff {
      \set Staff.instrumentName = #"I"
      \set Staff.shortInstrumentName = #"I"
      \corI
    }
    \new Staff {
      \set Staff.instrumentName = #"II"
      \set Staff.shortInstrumentName = #"II"
      \corII
    }
    \new Staff {
      \set Staff.instrumentName = #"III"
      \set Staff.shortInstrumentName = #"III"
      \corIII
    }
    \new Staff {
      \set Staff.instrumentName = #"IV"
      \set Staff.shortInstrumentName = #"IV"
      \corIV
    }
  >>

Unfortunately the curly brace created for these four instruments is way too 
wide. Is there a way to shrink the vertical size of the curly brace for the 
GrandStaff (so that it would have the same width as the curly brace of a 
GrandStaff consisting of only two instruments)?


Thank you,
Ádám