To answer my own question:
Create an alias for the account that holds the shared folder.
In the account create a mail filter rule:
if anyof (header :contains "Received" "alias@example.com") { fileinto "path/to/folder"; stop; }
There is always a Received: line in the email headers that contains the alias address.
This avoids missing emails when filtering for To or Cc and the alias address was on Bcc. |