Adding extra staff line

[Ernie Braganza]

I have looked through some examples and I can't figure out how to add four
measures with extra staves for a harmony part. I keep getting an extra line
above the staff group I want (see picture). How do I avoid the extra blank
staves from being inserted?

Thanks for your help.

Here's my code:

\version "2.24.0"
\score {
  <<
% Start with one staff line

    \new Staff \relative c'' {
      c1| c| c| c|
      \break
% Create 4 measures with extra staves for harmony

      \new StaffGroup \relative c'' {
        \once \omit Score.TimeSignature
        <<
          \new Staff {
            g1|g|g|g|
          }
          \new Staff {
            e1|e|e|e|
          }
        >>
      }
      \break
% Go back to just one staff line

      c1| c| c| c|
    }
  >>
}