Establishing agreement. . . Ask the group what topic they want to cover. Ask someone to summarize the position the group is taking on an issue. Ask the group to summarize a decision. Ask the group if they agree with the agenda items.
Someone becomes defensive. . .
Don't cut him or her off, but suggest that he or she has a good idea, and now you want to see how that fits into the agenda, process or solution. Thank them for their concern and suggest that the group needs to hear from everyone.