To ensure that everybody receives a reply, direct students to respond to a message that has not already received a reply.
Third respondent offers an alternative view.
Fifth respondent adds documented research to further support the original position. Sixth respondent adds documented research to further support the alternative view. Seventh respondent summarizes the two positions and provides a concluding statement. Add an oral component in which students report to the class the highlights of their discussion. Let students establish their own topics and select their groups with a framework you provide.