The best way to work with participants that are excited to share is to find them a way to have an active role. Perhaps ask them to help manage the chat during a virtual delivery. Or if in person, make them responsible for the customer count chart. When opening up topics for discussion, address the person straight on, “John, I'm sure you have experience with this but first let's hear from Sarah.”  This public statement acknowledges the person’s knowledge and many times, is enough to reduce their impulse to be the first to always answer or comment.