[Exim] Filter BCC

Newbie question...

I have some virtual hosts on my server. I use a Transport to deal
with emails delivered for that domains:

virtual_local_delivery:
driver = appendfile
group = mail
mode = 0660
file = /var/spool/mail/${lookup {$domain} dbm {/etc/exim/virtual-
domains} {$value} {fail}}
user = ${lookup {$domain} dbm {/etc/exim/virtual-domains} {$value}
{fail}}

The file /etc/exim/virtual-domains is a DBM file with "domain:user"
pairs. All emails sent to a domain that matches will be delivered to
that user.

I built a .forward file on each user´s home dir to redirect the
emails according to the user receiving it. Example:

All emails sent to domain.com will be delivered to a user
called "domainuser". In it´s home dir, we have a .forward file
looking like this:

# Exim filter
if $header_to: contains "daniel@???" then
deliver daniel@localhost
endif
if $header_cc: contains "daniel@???" then
deliver daniel@localhost
endif
if $header_to: contains "john@???" then
deliver john@localhost
endif
if $header_cc: contains "john@???" then
deliver john@localhost
endif
if not delivered then
deliver domain@localhost
endif


The problem is: many mailing lists use BCC: to deliver their email.
So this filter above won´t work correctly. I mean, if john@???
subscribe to a mailing list, or if somebody send an email to him
putting his address at BCC:, he´ll never receive that e-mail.

Is there anything I could do? Is there a better way to receive emails
to virtual hosts?

Thanks,
Daniel Wey