Start by asking the members of the group who only want to chatter to leave the room.
Sit in a circle on stools or hard chairs. Notice how many members are pulling one or both shoulders up to their ears, and how many heads are pulled to one side or pulled down and back with chins poking forward. The reason for this is that in withdrawal, muscles on the side of the neck shorten. This unbalances the head, and because it is so heavy (about one and a half stones), it puts a strain on the neck and shoulders that goes right down the spine through the pelvis to the knees. That is why so many people complain of weak aching knees. Notice how many people are pulling their feet back under the chair, or have their legs crossed.
Retraining muscles involves learning where tensions are and, without causing more tension by trying too hard, letting them go. The blur of aches and pains all over that people endure are often nothing more than tension. The pain-relieving chemicals produced by the brain are disturbed during withdrawal and that is why pain from old injuries or scars often reappears for a time.
If there is a teacher of the Alexander technique in your area you would not regret money spent on some lessons. The principle of the teaching is to show you how to live in the world without your body reacting to stress.