I have managed to get Boone, ED-E, and Lilly to follow one of my characters at the same time...I tried to get this to occur again and could not dupe it. I had Lilly and ED-E with me and went to the Lucky 38 and Boone joined up with me too. They dont seem to like anyone and they are pretty efficient at murdering everything, save 3 or 4 deathclaws at once...
I was just wondering if anyone else had this happen yet.

I finally made a video on my cell phone showing this...
http://www.youtube.com/watch?v=Wr-iaBHd25M