1\version "2.19.80"
2
3\header {
4  texidoc = "@code{\\new} can create a sibling of an existing context
5with the same type and name.  The instrument name should be PASS."
6}
7
8\new StaffGroup = "A" <<
9  \context StaffGroup = "B" \with { instrumentName = "PASS" } <<
10    s1
11  >>
12  \new StaffGroup = "B" {
13    %% This does not replace PASS because it is a new context, and it
14    %% is not engraved because this context contains no music.
15    \set StaffGroup.instrumentName = "FAIL"
16  }
17>>
18