Monday Hour One

Hi there- just watched the whole module for MHO and very excited to started with this but a few questions about how to manage a calendar that is at the mercy of others in my company. If others in my company set meetings for 1 hour and they always go over what is the best way to handle this? It feels like 30 minute meetings invariably go an hour or more and 1 hour meetings go, well, sometimes 2 hours making it so hard to get done everything thats on the calendar. How do suggest implementing this system when the majority of other stake holders don’t follow this same process?