VISA interview for Parents and sister together?

[immihelp]

Hello

I am H1b holder and I would like my parents and sister to visit US.
My dad works in govt. mom is house wife and sister is studying BAMS.


Should we get visa interview together for all of them or separate for parents. Which is more likely to get succeeded ?

[immihelp]

Either way is fine.

Each applicant is looked at separately.