Visa for Parents, Sister and BrInLaw

[hello123]

I am getting married in the US in August. My family in India are planning to come on a visitor's visa for the wedding, which includes my Mother, Father, Sister (Doctor, age 33) and BIL (Doctor, age 34).
Please advice me on which is better.... to attend for their visas all of them together OR let my Parents apply first and then after a few days, let my Sister and BIL apply for theirs.

Thanks

[VisaChief001]

Parents alone.