It’s called an “indaba” (pronounced IN-DAR-BAH), and is used to simplify discussions between many parties.
An indaba is designed to allow every party to voice its opinion, but still arrive at a consensus quickly. It works because opinions and arguments can only be aired in a particular way:
Instead of repeating stated positions, each party is encouraged to speak personally and state their “red lines,” which are thresholds that they don’t want to cross. But while telling others their hard limits, they are also asked to provide solutions to find a common ground.