You will need all the right people in the room (metaphorically).
Otherwise, you’re not going to get the right outcome.
You will probably have to come back and do it again.
Or catch them up, individually.
Then get everyone back together again anyway.
It may take longer to get all the right people in the room from the beginning.
But once you have, then you will be able to progress faster.
“Have the right people in the right places, working together.” — Roger Staubach
“Meetings should have as few people as possible, but all the right people.” — Charles W. Scharf