This list is not exhaustive. Please see the student's booklet for suggestions to students to h elp solve these and other problems. Express your concern. Give students a simple, practical exercise. For example, ask a student to present an opinion in a sentence or two and then ask two students to restate the sentence in their own words.
Rep eat for each student.
Or you could ask a student to voice an opinion and then ask another student to disasgree with the opinion but without attacking the person. Review with students the hand-out given to them about how to sucessfully interact with each other. Encourage students to provide feedback on the effectiveness of their interactions. Students need to feel comfortable to switch from talking about math to talking about groups dynamics. Insist that when a student makes a complaint, he or she provides some sort of suggestion to remedy the problem.