Split the group into two equal teams . Have three blown up balloons tied up above each team. Say there is a sweet / chocolate for everyone that listens well , if anyone doesn’t listen you will burst a balloon from their side if all the balloons are popped that team forfeits their rewards they are given to the other side. You rarely have to burst more than one balloon. There is a lot of peer presure on the usually disruptive children. At the end of the meeting say they can take their reward IF they feel they have deserved it. You will be surprised at the honesty from those you would least expect to be honest. You can then call that person back and reward their honesty.