RemoveEmptyStaffContext and Nr of Pages

[Toine Schreurs]

The following example results in 2 pages of output. But
if I enable the RemoveEmptyStaffContext, the number of pages
should obviously reduce to 1, but remains 2.
Is there a method to reduce the number of pages?

%========= start ============
\version "2.11.37"
\paper {
  ragged-last-bottom = ##t
  ragged-bottom = ##t
}

\layout {
  \context { 
%    \RemoveEmptyStaffContext
  }  
}

testmusicA = \relative c'' {
  \repeat unfold 60 { c1 }
}
testmusicB = \relative c'' {
  \repeat unfold 20 { c1 } 
  \repeat unfold 40 { R1 }
}

\score {
  \new StaffGroup
  <<
    \new Staff {
      \testmusicA
    }
    \new Staff {
      \testmusicB
    }
    \new Staff {
      \testmusicB
    }
    \new Staff {
      \testmusicB
    }
  >>  
}
%========= end ============

I am trying to typeset a (French) score from the percussion parts of on opera.
Every instrument on its own staff. Bassdrum, snare, cymbals, triangle,
Bells, Tamtam....  With lots and lots of rests, this results in a
60 page score, where every page is only half filled.

Toine Schreurs