You can do this via an advanced theme, but it needs a little change to the core code first, in order to retrieve the user's type (or 'level') from the database.
In qa_db_posts_basic_selectspec(...) in qa-db-selects.php, add:
... after ...
Then you want to override function post_meta_who(...) in your advanced theme. You can access the user's level from $post['raw']['level'] within that function, and compare that value against the QA_USER_LEVEL_* constants defined at the top of qa-app-users.php.