I have been using ddigest and successfully importing individual
digest messages into a pseudo-newsgroup. What do you mean by,
``some of the entries being overwritten.''? I have gotten messages
from yarn's import like, ``20 duplicate messages rejected''. But
to my surprise I found DDigest was correct, and there were duplicate
messages in the original digest.
One does have to delete the original single digest mail manually after
running ddigest on it to get many messages.