This factor is a key part of the problem. People trust people like themselves, hence they will favor people like themselves in hiring.
I suspect to truly make an impact, you need to do more than scrub photos and structure interviews. You need to convince those within your company that the goal is to hire people to fill in where the company (and its employees) are lacking.
Convince them that hiring those just like themselves is redundant, it won’t address weaknesses or give new perspectives.