> In our opinion the centennial edition is better characterized
> as a group of texts within one single text, but are there
> advantages which make one of the alternatives more preferable
> than the other?
Thanks for asking; I've been struggling with this issue too.
I don't think there is a 'correct' choice here. It'll depend on
the aspects you want to stress. If you use the 'groups of texts'
approach you're emphasizing the fact the poems may be considered
as independent works, tracing perhaps their history as they
appeared in individual editions.
I'm working at present on encoding emblem books, where I feel
(now, this may change) the poems and motto's within a single
emblem might be considered text-elements within a group. This
would emphasize the aspect of a mosaic each emblem (also)
has; but of course, the emblem may also be viewed as a
single text (or alternatively, the whole book might be
a single text): after all, it was published as a whole.
The Guidelines of course describe the use of the group-element
(section 7.3) in an example which looks very much like the one
you're describing. I think that fully justifies your approach.
The only advantage I can imagine to sticking to the use of div's
is that you might have ready-made stylesheets which suppose
you've been using div's; but then, you may easily convert the
text's to div's before running the stylesheet.