Kolab is offering a mail filtering feature. That makes it possible for Jane to apply a series of actions to specifically selected incoming emails, so that incoming mail meeting a certain criteria can be automatically processed by the server and handled/organized according to the defined actions. For example the server can move the message to a specified folder, redirect it to another account, send a reply, discard, delete, etc for as long as the defined criteria is fulfilled.
Filtering is based on the Sieve language, which means that under the hood all filters are stored in one or more Sieve scripts on the server. The filters can be managed through the Kolab web-client and allows Jane to define rules and actions in an easy way without the need to know the language.