In Moodle 2.0, blog is exclusively user-centric. You can search for blog entries written by members of a course, but you cannot restrict the visibility of these entries to a given group or course. A given user's blog entries are either visible only to himself (draft), to the entire site or the world (published through RSS).

This means that some existing code has to go, but since it doesn't really work that shouldn't be a problem.