To motivate everyone to take part in a group discussion and listen to each other, I sometimes ask them all to be secretaries and take notes on what they discuss and any opinions people in the groups have or decisions they make.

When the discussion is finished I put them in new groups and each 'secretary' has to report to the new group on their discussion.

It works really well with higher-level students.

http://www.teachingenglish.org.uk/try/tips/group-secretary