In SV, is racial hiring a thing?

If a company has many employees ethnically from the Indian subcontinent will they be just as likely to hire a white person, black person or East Asian person?

My feeling is that they would rather hire people from the same ethnic background.

Am I a horrible racist, or is there truth to this (or maybe both for saying something, even if true)?

Equally importantly, is it harder to break into a predominantly white or Asian work culture, if you're not from that background?

Is it possible to say that there is some ethnic group that is more open to hiring outside itself, and some that are less open, based on experience in the valley?