I've evaluated one of these group exercises for a grad program before. One thing that stuck out like a sore thumb was out of the four individuals there was one

I've evaluated one of these group exercises for a grad program before. One thing that stuck out like a sore thumb was out of the four individuals there was one guy that continually derailed the group, and there was another guy who even though the other guy was always derailing things still showed courtesy towards him and listened to his opinions. The other two guys were both reasonable and I liked them too, but the guy whom I both liked and who showed courtesy to an individual I would describe as "difficult" was one of the ones we wound up hiring. He got glowing reviews from pretty much every assessor and went on to become a great colleague to work with. I think any of those three out of the four people would have been fine hires, and the other guy was a strong no-hire.