Re:centering text

[simon blackmore]

Hi Everyone,
Thanks so much for all the answers, its great when you get a few  
different
solutions.

I think Davids solution seems pretty much what I need. But I think it  
needs a tweek.
The << seems to throw an error. I	f I don't include it, I get the text  
in the right sort of
place but on bar 3 and 4 rather than 1 and 2.

\header {
title = "hello world"
}

\new RhythmicStaff {
  \new Voice = "myRhythm"  <<
  {
    \time 4/4
    r8 r8 r8 c8 r8 c8 c8 r8
    c8 r8 c8 r8 r8 c8 c8 r8
  }
  {
    \override MultiMeasureRest #'transparent = ##t
    R1-\markup { \center-align bar1 }
    R-\markup { \center-align bar2 }
  }

}

Any ideas on that.

Thanks again.

Cheers

Simon