Many of my sisters and I were friends with NPHC members. We supported our NPHC friends, and they supported us.
When we had Greek Olympics, the teams were made up of an IFC, NPC, and NPHC org. It was only one week, but it was a good way to get to know each other.
I think that I personally knew many NPHC members because my freshman Resident Director was a Kappa Alpha Psi alumnus and was very involved with his fraternity. They lived and hung out in my dorm so I got to know most of the brothers. My sophomore and junior years I served on IGC and met the reps from all the sororities and fraternities on campus. I was the social coordinator/events activity chair so I put together a calendar of every group's philanthropic and community service activities so we wouldn't have a timing conflict and we could attend each other's events. We built a great spirit of friendship and support among all of the groups. Plus we had a lot of fun. Never underestimate the fun factor in getting people involved.