Alias for Multiple Users

Is this Possible?
I saw, when you add names into the 'deliver_to' field it tries to
deliver the mails external and because there is no host-part in the
email it appends the default one so it works for one domain. For a
non-standard domain (e.g. the default-server-name is highpop.de, the
non-standard superduper.de) it will append 'highpop.de', too, so you
will have to add the full email adress to the database. But the field
has only 250 characters... I don't want to change this because I don't
know if dbmail will work after this (would it?).
My idea is to add the idnrs of the users in the database, but this
doesn't work with the version I use (1.2.1). Will this be available in
later versions? Or has someone allready wrote a patch?

Sorry for my discomposure but I have so many things in my head about this
and I don't know which one to tell first o_0