Selectively BCC ALL emails using postfix by domain.

You can use sender_bcc_maps and recipient_bcc_maps to selectively BCC both incoming and outgoing emails.

sender_bcc_maps = hash:/etc/postfix/archive_domain
recipient_bcc_maps = hash:/etc/postfix/archive_domain

In /etc/postfix/archive_domain Add one entry per domain
@domain.com archive@archivedomain.com

Then run
postmap /etc/postfix/archive_domain

Reload postfix configuration

service postfix reload

You can now handle mail to @archive.example.com however you please.