How to Avoid Infants at Reception

My FH and I are having a very formal, elegant reception. We really do not want screaming children at the reception. However, I am being forced to invite first cousins, which includes teenagers and children over the age of ten, which I am completely fine with. It gets complicated from there though, because apparently I have to invite my cousins’ children, who are ages 4 and 2. Then it gets even worse, because my FH’s sibling will have a three month old child that they’ve already mentioned bringing to the reception so the whole family can meet the baby. I can’t specify adults only, because then I’m not inviting most of my first cousins on one side and family is not alright with that. But now that I have to invite children of ten years old, I’m also being forced to invite children even younger, as well as infants. This is not acceptable, but the lines get so blurry with ages because I’m already forced to invite young children. I don’t know how to maneuver this to avoid having infants at the formal reception, and I don’t know where to draw the line.