variable in paper block

[Stefan Thomas]

Dear community,
I would like to make a substition in the paper block, for the part
title. I usually use:
\paper{
 oddHeaderMarkup = \markup
 \fill-line {
 "name of the part"
 " "
 \on-the-fly #print-page-number-check-first \fromproperty
#'page:page-number-string
 }

 evenHeaderMarkup = \markup
 \fill-line {
 \on-the-fly #print-page-number-check-first \fromproperty
#'page:page-number-string
 " "
 "Bassklarinette"
 }
 }
But I would like to do something like: \partname #'"Violin 1" or
\partname #'"Violin 2" etc.
How can I do this?