shared notes across piano staff

[Robert Garrigos]

Hi,

I have this piano excerpt I’m trying to reproduce:


and I have this code:

\score {
  <<
    \new PianoStaff
    <<
      \new Staff  \relative c' {
        \key g \minor
        \time 3/4
        |
          {  ef4^( c d~ | d8 c bf!4 a) }

      }
      \new Staff  \relative c' {
        \key g \minor
        \time 3/4
        \clef bass

        | <<
          { \omit TupletBracket \omit TupletNumber \tuplet 3/2 4 { r8 ef, a c, 
ef a d, af' b | r8 c, g'  bf  d, g a d, fs} }
          \\
          {  }
          \\
          {  }
        >>
      }
    >>
  >>
}

which gives me:


how can I have the bf and the a in the second measure shared across the staves??

Thanks

========================
Robert Garrigós i Castro
Web personal: https://garrigos.cat
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