Convert a webinar to a meeting DURING the webinar.

I'd like to have a webinar which starts as a standard webinar, but after the panelists' presentations allows ALL attendees to un-mute their audio AND video for the discussion.

Currently I set up two events, a webinar and meeting. Everyone has to leave the webinar and joint the meeting for discussion. It's a huge pain and we always loose a bunch of people.

I don't want to use chat or Q&A. I suppose a "promote all attendees to panelists" function would work. Typically, we have 20-50 attendees.