extra space at a line end before a new staff

[Nicolas Sceaux]

Hi,

How can I get rid off the extra space following the last bar of the
first system, in the following example:

\version "2.5.0"
\layout { raggedright = ##t }
\new StaffGroup <<
    \new Staff { g'1 g' g' g' }
    \new Staff { 
        c'1 c' 
        << 
            { \break e'1 e'  }
            \new Staff { 
                \override Staff.TimeSignature #'transparent = ##t
                c'1 c'
            }
        >>
    }
>>

I tried to put staff-bar at the end of break-align-orders
(end-of-line), but with no success.

nicolas