I'm not sure how hiring a diverse team (only) will help. It seems like it will just create two different groups within the same company/workgroup that stick together and don't talk to one another. Sure, the minorities will feel more comfortable, but I think communication and acceptance between all parties will help overcome the "out of place" feeling in a much more enlightened way--a much more enlightened way instead of hiring people for your odd men/women out to hang out with instead of those _other_ people.
Now, if hiring a diverse team forces the old team to start realizing their biases and become more accepting, that a great way to start to overcome those barriers, but I think the understanding is far more important than just having a higher percentage of people of other races.
Agreed there's more to it than just hiring the diverse team, but that's a chunk of it.
People work together, and project assignments aren't made to put friends together, but to group the skillsets needed and to help people do the work that interests them.
Of course there's some time spent hanging out in the break room or possibly after-hours, but most socializing (in my experience) happens around work, in groupings that are work-project based.
The small talk is quite different (and honestly, much more interesting!) when you have a more diverse group, automatically.
Now, if hiring a diverse team forces the old team to start realizing their biases and become more accepting, that a great way to start to overcome those barriers, but I think the understanding is far more important than just having a higher percentage of people of other races.
I discuss my opinion on this in my comment below.