Ask HN: How do I get the mark important feature from GMail to my hosting?

Spamassassin and bogofilter seem to only differentiate between no spam and spam mails. But I want my marked as important, okay, spam, so I only get interrupted in my workflow if one important message was received.

My first thought was to setup two bogofilter demons, one for marking spam and one for marking important things, but that doesn't seem to be the right way to do it.