funny construction

[Br. Gabriel-Marie | SSPX]

I'm stuck, y'all.

I have a song that goes like this:
----------------------------------
soprano
alto
    15 lyric verses in between
tenor
bass

soprano
alto
    just one lyric in between - it's the chorus
tenor
bass


soprano
alto
    15 lyric verses in between \repeatOfFourWords
tenor
bass
----------------------------------
How do I lay this out?  I have two problems:
1. How do I get the center staff to be not connected to the other two?
2. How do I make three separate staffs?  The code I have right now makes one giant staff and tries to play all three of them at once.

Right now, I've got this, which is wrong -


\score {
<<
    \new StaffGroup <<
            \new Staff<<
                \new Voice = "altoTop" \altoTop
                \break
            >>
            \new Lyrics \lyricsto "versesTop" { lyrics... }
            \new Lyrics \lyricsto "versesTop" { lyrics... }
            \new Staff<<
                \new Voice = "bassTop" \bassTop
                \break
            >>
    >>
   
    \new StaffGroup <<
            \new Staff<<
                \new Voice = "altoCenter" \altoCenter
                \break
            >>
            \new Lyrics \lyricsto "versesCenter" { Ti -- rou -- li, ra -- ta -- plan, ra -- ta -- plan. }
            \new Staff<<
                \new Voice = "bassCenter" \bassCenter
                \break
            >>
    >>
   
   
    \new StaffGroup<<
            \new Staff<<
                \new Voice = "altoBottom" \altoBottom
            >>
            \new Lyrics \lyricsto "versesBottom" { lyrics... \choruslet   }
            \new Lyrics \lyricsto "versesBottom" { lyrics.... \choruslet   }
           
            \new Staff<<
                \new Voice = "bassBottom" \bassBottom
            >>           
           
    >>
>>
    \layout {
        \override Lyrics.VerticalAxisGroup #'staff-affinity = #CENTER
    }
}