Re: What would you do??
That's tough. If you don't know the exercises intimately, how are you going to demonstrate well for 40 people much less teach them?
One exercise for example that teaches harmonising is to have uke grab ryotedori and push down. Nage brings hands down to touch the floor. Granted, you already have the same motion going, so its a good start because you're connecting with the ki direction. But even so, if you pull or tug uke, uke will fight back even though he started out going in the same direction.
Next, have uke pull up instead, but repeat the exercise. Nage brings down his hands to touch the floor.
3rd. Have uke do what he wants, but nage maintains the same feeling and moves around now and finally touches the floor.
The idea is to have nage find a way to work together with uke, instead of competing with him to bring his hands down, but cooperating.
Other ways is to just to explain tenkan and irimi. Tenkan is to see the other persons point of view. Irimi is to advance under difficulty. Both physically translates well as a mental exercise.
Another good one is to have 2 ukes grab morotedori on both your hands. Grab and 'do' something that is. And you just use each others energy against each other to take their balance and maintain yours. Keeping center and relaxed. That's a good exercise when an employee is hassled by different people who are competing for his attention.
I would start with aiki taiso and rei ki tests though... those are good for almost anyone.