I would also demand respect for what you have to say, by stopping them every time they interrupt you. Make them aware of their bad behavior. You can do this by holding up your hand, "Stop"! I wasn't finished...." Do this politely and firmly every time they trample in to your thinking space. If they complain that they can't remember what THEY were going to say next, crisply tell them to make a note to themselves.
I swear, bad meeting manners is a plague here in Western Canada. I have to keep reminding these self-made cowboys how to behave. Being too polite to interrupt others, I have learned to make notes of critical thoughts to add to the conversation...when I have a chance. When I conduct a meeting, I won't allow two conversations at once. I'll make everyone stop and make them repeat themselves...one at a time. I'm nice about it. I say, "I want to hear what everyone has to say, please continue." After all, that's what meetings are for, to gather ideas and thoughts from everyone in the room. *rant over*
If you study the servants and slaves of the bible, asking WHO these characters represent in current WT eschatology, also ask WHY they believe that. Why is one scripture interpreted one way and another not?