very long rests...

[Arno Waschk]

dear list,

i have the following problem:

I have a pretty long score (1+ hour, 1200+ bars) with many time changes 
(800+ i guess).
Now at several points the thing i need to write is "Multi-measure-rest 
until bar 1100" or a similar long skip. Where bar 1100 could have a 
label or the like...
The only way i see is to manually calculate the length of all the 
individual measures until the point i want it to be and then write 
"R1*7453/16" or so...
Remember the many many time changes, so it would not be simply R1*1100 
from the beginning, or R1*500 from bar 600 ...
Is there something to make lilypond calculate that length by itself?

thanks for any hints!

yours

arno