The Purge Rooms tool for Interaction provides a dialog so you can purge all the statements in selected chat rooms. This tool is useful for example to clear the room after a conversation so that the statements don't carry over to the next discussion. The dialog has checkboxes for each room, so you can purge multiple rooms at the same time:

The new Tool will show up as an item on the Tools menu after the next time you restart the application, or if you select the Edit Tools item of the Tools menu.