[Exim] aliasfile director and duplicates

I have a requirement to meet which involves delivering multiple copies of
the same message to a particular alias if specified via the recipient
list. As an example, say I have several aliases defined...

foo: mbox
blah: mbox

... where mbox is a valid local mailbox. If someone sends mail to foo and
CCs blah, then the duplicate copy is removed and only one copy is
delivered into mbox. I understand that this is usually desirable, but
there's no accounting for the weird requirements that customers have - I
need to avoid eliminating the duplicates and deliver as many copies of the
message as recipients. I have a work-around in place, but it's ugly.

Might it be possible to add an option to the aliasfile and/or smartuser
directors which would allow an administrator to disable the duplicate
elimination? Such an option would be extremely useful to me right now :)

--
Pete Naylor