Don’t really know if this is sth. to post on this forum, but I tried to make a sieve filter which tags mails from my contacts by the category of the contact. Seems this feature is available in Protonmail:
require [“fileinto”, “extlists”];
Checks that the sender is in your personal address book
if header :list “from” “:addrbook:personal?label=Family”
Would it be possible to implement such feature also in mailcow?