[exim] unseen redirect router

I have a few accounts which I monitor with an unseen redirect router.
One local delivery may explode to several other local deliveries via
a dot forward with multiple names.

My unseen router sends copies of these deliveries to me as desired, but
since there are multiple different deliveries I get multiple unseen deliveries
as well (of the same message).

Is is because the router is "unseen" that the usual clever internal workings of
exim (which prevents multiple copy deliveries) is being circumvented?

If so, is there a directive I can enter -anywhere- which would prevent duplicate
deliveries to my unseen mirror? All deliveries are local, both the end user and
the unseen mirror.

Thanks!