Indicating cross-staff chords with a bracket

An arpeggio bracket can indicate that notes on two different staves are to be played with the same hand. In order to do this, the PianoStaff must be set to accept cross-staff arpeggios and the arpeggios must be set to the bracket shape in the PianoStaff context.

(Debussy, Les collines d'Anacapri, m. 65)

\version "2.24"

\new PianoStaff <<
  \set PianoStaff.connectArpeggios = ##t
  \override PianoStaff.Arpeggio.stencil =
    #ly:arpeggio::brew-chord-bracket
  \new Staff {
    \relative c' {
      \key b \major
      \time 6/8
      b8-.(\arpeggio fis'-.\> cis-.
        e-. gis-. b-.)\!\fermata^\laissezVibrer \bar "||"
    }
  }
  \new Staff {
    \relative c' {
      \clef bass
      \key b \major
      <<
        {
          <a e cis>2.\arpeggio
        }
        \\
        {
          <a, e a,>2.
        }
      >>
    }
  }
>>