Slurs in Chords

[Stephen Sheasby]

Hi all,

I am clearing slides for our church music projection and am having some areas 
of difficulty particularly with slurs. If I enter the notes as separate voices 
the slurs are correct but if I combine them as a chord or use part combine I 
only get one slur. 

This first example shows the slurs as they should be but the parts are not 
combined:

<code>
\version "2.18.2-1"
\language "english"
sopranoNotes = \relative c' {
        b4 c d( f8) b8\rest \bar "||"
}
altoNotes = \relative c' {
        g4 a b( a8) r8
}

\score {
        <<
%                       -- Women's staff
                        \new Staff = women
                        <<
                                \clef treble
                                \new Voice = "sopranos"
                                        { \voiceOne << \global \sopranoNotes >> 
}

                                \new Voice = "altos"
                                        { \voiceTwo << \global \altoNotes >> }
                        >>
        >>
}

</code>

If I use partcombine I get the notes combined as desired but only one slur:

<code>
\version "2.18.2-1"
\language "english"
sopranoNotes = \relative c' {
        b4 c d( f8) b8\rest \bar "||"
}
altoNotes = \relative c' {
        g4 a b( a8) r8
}

\score {
        <<
%                       -- Women's staff
                        \new Staff \with { printPartCombineTexts = ##f } { 
                        \partcombine \sopranoNotes \altoNotes }
        >>
}

</code>

Is it even possible to do what I need?

Thanks so much for your help and suggestions:

Stephen