\magnifyStaff for a staff group?

[Kieren MacMillan]

Hello all,

Please consider the following snippet, the first part of which works as 
expected and the second part of which fails:

%%  SNIPPET BEGINS
\version "2.19.59"

\score {
  <<
    \new Staff c''1
    \new PianoStaff
    <<
      \new Staff \with { \magnifyStaff #5/7 } c''1
      \new Staff \with { \magnifyStaff #5/7 } c''1
    >>
  >>
}

\score {
  <<
    \new Staff c''1
    \new PianoStaff \with { \magnifyStaff #5/7 }
    <<
      \new Staff c''1
      \new Staff c''1
    >>
  >>
}
%%  SNIPPET ENDS

Looking in music-functions-init.ly, it’s easy to work out *why* the second 
score throws an error. My questions are:

1. Is there a simple (e.g., single command) way to change the size of a whole 
staff group?

2. Regardless of whether such a thing already exists, is it somehow preferable 
to keep the magnification work at the Staff level, or would some syntactic 
sugar (e.g., \magnifyGroup) be a nice feature?

Thanks,
Kieren.
________________________________

Kieren MacMillan, composer
‣ website: www.kierenmacmillan.info
‣ email: address@hidden