Slur in different voices

[Mark Probert]

Hi.

I have a score that, in the piano, has a slur crossing voices (in the 
example the slur would end up with the B being held for a 4 count). 
There is a note in the LP manual saying that slurs must all stay in the 
same voice, so is there a work-around for this kind of thing?

Many thanks!

 .. mark.

----< code >-----
\version "2.22"

global = {
  \key c \major
  \time 4/4
}

%%% ------
%%% piano
%%%
upperA = \new Voice \relative c'
{ \voiceOne
  s1 | s1
}

upperB = \new Voice \relative c'
{ \voiceTwo
  s1 | s1
}

lowerA = \new Voice \relative c'
{ \voiceThree
  s1 | b2 f2\rest |
}

lowerB = \new Voice \relative c
{ \voiceFour
  f2\rest b2 | c,2 s2 |
}


%%% -----
%%% staves
%%%
\score {
  <<
    \new PianoStaff <<
      \new Staff <<
        \clef treble
        \global
        \upperA
        \upperB
      >>
      \new Staff <<
        \clef bass
        \global
        \lowerA
        \lowerB
      >>
    >>
  >>
  \layout{}
}