Two addit. lyrics lines -- how to make centered?

[Dmytro O. Redchuk]

Hello,

   I want to add lyrics to voice and have additional lyrics for some
   measures (which may have additional voice -- upper tenor, let's say) --
   and i don't know how to do it best :-)

   Just take a look at the code:

        %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

        melody = \relative c'' {
                g a b c
                <<
                        \new Voice = "tenorup" {
                                \voiceOne
                                b a g f
                        }
                        \new Voice = "tenorlo" {
                                \voiceTwo
                                % s s s s
                                c c c c
                        }
                >>
                e d c c
        }
         
         
        mainwords = \lyricmode { c d e f g a b c }
         
        upperwords = \lyricmode { u u u u }
        lowerwords = \lyricmode { l l l l }
         
        \score {
                \new Staff = "tenor" <<
                        \new Voice = "tenvoice" {
                                \melody
                        }
                        \new Lyrics = tenlyr \lyricsto tenvoice \mainwords
                        \new Lyrics = tenlyrup
                                % \with {
                                %       alignAboveContext = tenlyr
                                % }
                        \lyricsto tenorup \upperwords
                        \new Lyrics = tenlyrlo \lyricsto tenorlo \lowerwords
                >>
        }

        %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

    This code produces two lyrics which are lowered below "main" tenor's
    lyrics. Is there any way to raise them up (upper tenor -- above and
    lower tenor -- below "main" vocal)?

    If i uncomment \with {alignAboveContext = tenlyr } in that code --
    it's almost what i want, but i would like to have additional lyrics
    to be close to "main". Is there any way to do this?

    What i want exactly: to have behaviour like in this fragment --
    http://www2.ldc.net/~dor/kanon006.jpg (was typed with
    musixlyr/musixtex, 28K)

Thanks!
-- 
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        `    G.m-"^m`m'        Dmytro O. Redchuk