Kid problem

Hey I have a problem my twin sister has quintuplets and 2 sets of twins that's 8 kids in total ( I know alot) and all are under 7 years of age how do I politely tell her I want her and her bf at my wedding but not her kids. My wedding is kid free except for my daughter who is the flower girl and ring bearer. I love my nieces and nephews dont get me wrong I do but that is to many to one keep quiet and still and to keep up with. My sister is saying she cant leave them cause they may get hurt with the baby sitter aka her bfs mom I dont want to make her leave them but it's my day so how do I say leave your kids at home without being rude