Seba presentation and facilitation for learning are very different.
If they have grown rapidly then most likely they are struggling with increased complexity and the transition from being flexible and nimble with little in the way of structure and process to having to introduce more of this to help manage the complexity.
Communication is usually the problem in situations like this.
Give their business focus - dispute resolution - how about something around coaching? That aligns to both their likely internal challenges and their own core competency.
I'm sure you're familiar with a number of coaching models. You could write a short role play briefing, introduce the coaching concept, explain the theory and then have two of the audience do the role play with you coaching them afterwards. Or better still have the other two audience members coach them. That way everyone has a chance to practise the application.