I want to have a graduation event exclusively for an underrepresented race
Why do you want to hold such an exclusive event?
I think ignorance lingers around here, but I think they do want it
Even if there is some support for such an event, there might not be enough people to make it worthwhile. Besides, it's time to bring people together, not separate them.
I know, I'm trying to introduce those people who want to be there with common interests to each other.
Well, this is also a form of segregation in some ways although you might not realize it. Just accept a normal graduation and make it so that everyone is welcome and not seen for their race at all.