To 'have a meeting' is a dynamic use of the verb - the same as have a walk , a talk , a discussion, an argument, a fight or a million other things that you can 'have' or 'be having'. 'Have' is only a stative ( non -continuous )verb when it means 'possess' - as in 'I have blue eyes'. In all other cases, it is dynamic and can be used in continuous tenses.