Cross staff stems between notes of different durations

[Andrew Bernard]

If one wants to have cross staff stems between notes of different
durations, found often in the contemporary music I set, is there a
lilypond setting of some sort to do this? Currently I have to use the
technique shown in the MWE here. This works fine - it is just when
there are a large number of these occurrences it becomes tedious.

Andrew

== snip

\version "2.19.45"

treble = {
  \clef treble
  \time 1/4
  \stemDown
  \crossStaff { a'2 }
}

bass =  {
  \clef bass
  \time 1/4
  \autoBeamOff
  <<
    {
      b8 b
    }
    \new Voice
    {
      \voiceTwo
      b2*1/2
    }
  >>
  b4
}

\score {
  \new PianoStaff
  <<
    \new Staff = "treble" \with {
    }
    { \treble }

    \new Staff = "bass" \with {
    }
    { \bass }
  >>

  \layout {
    \context {
      \PianoStaff
      \consists #Span_stem_engraver
    }
  }
}


== snip