The Kappas at my school are a part of the IFC. I know the Alphas at UVA, and BLK is SOOO right--they catch it because they are a part of it too.
Honestly, no one at my school really said anything about the Kappas joining the IFC because they don't do anything. Panhell doesn't do anything. All Greek Council doesn't do anything. (Sadly, the Black Greeks haven't even had the NPHC for a whole year, so they don't do much either.) Everyone is more about doing what their particular organization does--ALONE. There are not a lot of collaborations (or none that require a lot of time, planning, or talk of splitting the profit). The meetings are pointless.
What I've noticed with white frats and sororities is pretty similar to BLK as well. About 50% of the guys are in frats and nearly 75%-80% of the girls. "Pledge night" for the girls--they go around to NUMEROUS parties and try to see who can "make-out" with the most guys! (It's SOOOO disgusting.) It's so bad that people put up flyers about catching mono and how the girls should try to be safe during the week of "pledge night." The campus is a "wet" campus, and I've talked to a number of guys in white frats who said that they have to use beer in order to recruit. And that is pretty sad.
We congregate because--that's where we feel comfortable. (Just like BLK said.) However, there are some blacks who don't talk to the "rest" of us--they only associate with the white students. (As in, if you see them in passing, they don't speak.) There aren't many of us here anyway, so it's impossible for us not to encounter someone of a different ethnic, religious, political, etc. background. I can truly say that the black students have the people skills to be able to associate with all types of people.
As for the international fraternity, those who are interested in Black Greek Organizations do not participate in formal rush because our organizations don't. We don't have bids or smokers. And in addition to that, our organizations are for life. They are supposed to help us remain dedicated to the community through service--beyond college. My understanding is that white fraternities and sororities don't stress this during formal rush or even while members are a part of the chapter. After graduation, the majority no longer work with their organizations. I don't know how you can stress this with your particular organization, Brave.
But if you want to get more black students, formal rush is not the way to go.