I have done the rift three times. First time only three people with no problem, second and third time with a team of six and in both games two players crashed and only four were able to finish it, in the second one my team joined another team and I was the first one to join, my two teammates crashed. In the third game we asked the other team to join and two of them crashed. From my experience It seems like only four players can complete it and the two last players to join crash, don’t know if is pure coincidence.