What should happen is once you've cleared the first boss fight and you've made it to the Jump Phase, those players should unlock matchmaking for the Raid. By then you understand what it takes to participate in the Raid. Those player matchmaking with you are familiar with the process and now it's allowing those hardcore Raid players a chance to come back and tackle end portion at later date with others. Becuase honestly even with a Clan you're never with all the same people twice, as it seems to me anyways.