Ok, here's the basic format of a JC.
1) bring you in and make small talk
2) explain why you are here
3) pray for holy spirit to come to the brothers and help them make a decision
4) berate you for being human and sinning, berate you for having doubts, berate you for the sake of berating you
5) read scriptures (see step 4)
6) excuse you from the room (brate you some more?)
7) invite you back in, give you an over view of the berating you received earlier.
8) inform you that you will be DF'd and you have one week to appeal.
(appeal process)
9) 3 different brothers berate you again for what you have/haven't done
10) DF you anyway
11) announce to the congregation you are no longer a JW
So, to answer your question, I don't know if it takes a majority decision. I think it does. But there seems to be a standard make-up of a JC. One brother who is genuinly nice and actually wants to help, another brother who doesn't know you well at all and seems to be the swing vote and another brother, a total @$$ hole who leads the whole deal.
Am I bitter?? HE!! YES I AM!
Whew, I'm done now.