repeats with 3rd stanza following

[John Kelly]

I'm trying to set a single vocal part. It has three stanzas with a refrain. The
music for the thirds stanza is slightly different from the music for the first
two, so I want the layout like this:

|: notes for stanzas 1 & 2 :| notes for stanza 3 ||
|: words for stanzas 1 & 2 :| words for stanza 3 ||

For some reason Lilypond cannot figure out what I want. I get only the first two
stanzas or all three stanzas crammed into the last section. 

How do I do this? I'm not new to LP, but this is baffling me.

Thanks,

John Kelly