This is snippet of system.filter from our setup which used by exim as system filter.
The outgoing messages was archived under two circumstances:
1. the target domain is in a list
2. has a attachment and target domain is local_domain
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# some domains
if foranyaddress $recipients (${lookup{${domain:$thisaddress}}lsearch{/etc/exim/archive/d omains}{$value}} is "yes") then
unseen save /var/mails/#marc#/Maildir/.outgoing.bydomain.${tr{${domain:$ thisaddress}}{.}{_}}/
# with attachments
elif
$h_content-type: begins multipart/mixed
and
foranyaddress $recipients (${domain:$thisaddress} is not "mydomain.tld")
then
unseen save /var/mails/#marc#/Maildir/.outgoing.withattachment.${length_ 6:$tod_logfile}/
endif
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