Your new best friend - your wedding planner.
See we have no problem telling someone that have to leave the building or aren't allowed to attend. If they are in the wrong place, we will tell them to please go to where they need to be. It isn't that we are cold and heartless. It is that we know what has to be done and we are detached from the emotions of the situation. At the end of the day, we don't have to be related to them or stay friends with them like you do. Having a wedding planner can save your relationship while still keep things running smoothly.