https://www.polygon.com/2018/5/11/17346080/destiny-2-warmind-escalation-protocol-nine-players

Escalation Protocol is one of the more exciting additions in Destiny 2: Warmind. It asks players to jump into a social space and take on an extremely difficult, wave-based challenge. That would normally be great, but players still can’t match into social spaces with more than two friends, a combined total of three players.

However, the social spaces can all hold nine, meaning that you have to hope for six other players that you can’t really coordinate with. Well, crafty Destiny 2 players have already found a workaround for this frustrating limitation.