this is indeed an interesting question. what Andrew does in this case
is simply to treat the alternatives as if they were enclosures, but to
label them as alternatives. What shows up is a compound doucment that
shows the "best recognized" alternative, and then is followed by a button
for each additional alternative. The buttons are labelled things like
"alternative version #1" and I think that users generally ignore them.
The truth is, if you recongize everything in the "preferred" alternative,
there's no good reason for even keeping the alternative version around,
but somehow I, like you, felt reluctant to throw away even this information
which was almost guaranteed to be redundant... -- Nathaniel