Including multiple scores in book/bookpart

[Sven Axelsson]

I have many files that each define a separate score. Sometimes I also
want to combine them using book/bookpart like so:

\book {
  \bookpart {
    \include "score1.ly"
    \include "score1.ly"
  }
}

and so on.

However, as noted in
https://lilypond.org/doc/v2.26/Documentation/notation/multiple-scores-in-a-book
the include will fail if the score contains variables, which it sometimes
does.

What is the best workaround for this case, where I both want to render the
score separately and include it in a bookpart?

-- 
*Sven Axelsson*
++++++++++[>++++++++++>+++++++++++>++++++++++>++++++
>++++<<<<<-]>++++.+.++++.>+++++.>+.<<-.>>+.>++++.<<.
+++.>-.<<++.>>----.<++.>>>++++++.<<<<.>>++++.<----.