Good question. In fact there is no goal to achieve agreement unless we might think about agreement on the overall landscape of the community and agreement of the extent to which the representation of diversity is indeed representative.
The greater the diversity the richer the end-product which aims to show multiple perspectives on the issue as seen by the community/class (group-situated).
As the process goes along individuals talk, listen and see different ideas that support their own thinking. At the end each individual can vote on the ideas they have generated (student-generated questions) to produce this portrait of diversity in context. Then we have a measure of collective thinking and a firm basis for further development.
I should just add that this is a face to face activity using networked classroom technology. The electronic product can be shared and discussed online but generating it online is more problematic.