We loosely model our discussions on various group-meeting dynamics, namely

For example, from this page (pdf) on the dynamics of the World Café process:

World Café is an easy-to-use method for creating a living network of collaborative dialogue around questions that matter in service to real work. Cafés in different contexts have been named in many ways to meet specific goals, for example Creative Cafés, Strategy Cafés, Leadership Cafés, and Community Cafés. World Café conversations are based on the principles and format developed by the World Café, a global movement to support conversations that matter in corporate, government, and community settings around the world.

World Café Guidelines: Conducting an exciting World Café Conversation is not hard—it’s limited only by your imagination!

The World Café format is flexible and adapts to many different circumstances. When these design principles are used together they foster collaborative dialogue, active engagement, and constructive possibilities for action.

1) Set the Context

Pay attention to the reason you are bringing people together, and what you want to achieve.

…  more at http://www.theworldcafe.com/wp-content/uploads/2015/07/Cafe-To-Go-Revise...

Insofar as "Set the Context" is concerned -- it's pertinent to recall a scene from Alice in Wonderland:

Alice (upon meeting The Cheshire Cat): “Would you tell me, please, which way I ought to go from here?”
“That depends a good deal on where you want to get to,” said the Cat.
“I don’t much care where—” said Alice.
“Then it doesn’t matter which way you go,” said the Cat.
“—so long as I get somewhere,” Alice added as an explanation.
“Oh, you’re sure to do that,” said the Cat, “if you only walk long enough.”