[kde-linux] Merging KMail mailboxes

[JCA]

   I have two KMail mailboxes, on two different machines, each
containing messages addressed to the same users. The contents of the
mailboxes overlap: Both boxes contain a number of messages in common,
but each of them has messages that the other hasn't. In addition, each
mailbox contains a hierarchy of folders, and the hierarchies on both
mailboxes differ somewhat.

   I would like to consolidate the contents of both mailboxes into a
single one. Is there a relatively painless way of doing this?