Kids And Weddings?

How do you politely say NO KIDS at a wedding? Also what if there are 3 kids in the wedding? Is it right to say no others? Also 2 of the 3 kids in the wedding are brother and sister (kids of bride`s cousin). There is another brother that we think is too young? How can we tell the bride`s cousin not to bring 3rd child?
Posted by Dave; updated 01/05/03