New Year`s Eve Wedding

I am having a reception on new years at 8:oopm and i have a 4yr old and 6 month old i thought i would just have them there with us until later on. I havent got a baby sitter in mind yet cause all family will be there. My sisters have said they are bring there kids and thats ok but i dont think that it will be ok to have them there until midnight. What should i do so that kids are not there all night. It is new years eve isnt that more of and adult thing???