variant on "many syllables to one note"

[Graham King]

In the early sixteenth century manuscript I'm working on, the scribe has
set the first three syllables of "angelorum" to a single note that I'm
transcribing as a1. ~ a1. ~ a1

Is there a way, preferably compatible with \lyricmode, to tell lilypond
to align the syllables under the respective semibreves?

(So far, I've tried the suggestions for "manual syllable durations" and
"multiple syllables to one note" in the Notation Reference manual)
-- 
Graham King <address@hidden>