postfix + spamasassin on outgoing email

For domain company.com,

I have server with postfix + dovecot + spamassassin.

Currently spamassassin works just before dovecot:

dovecot   unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail:vmail argv=/usr/bin/spamc -e /usr/libexec/dovecot/dovecot-lda -f ${sender} -d ${user}@${nexthop}

This is because we want to get all spam messages and put it in spam folder.

This means all incoming mails to [email protected] are checked for spam.

However, each email of company.com have access to SMTP relay via their user and password (sasl auth via dovecot)

I want to check all these outgoing / relayed emails for spam as well, while server accepts all spam for local delivery for company.com.

Any ideas?