Customize Breakout Rooms?

I have an event coming up and we'd like to have one breakout room open all the time to use as our Help Room. Is there a way to keep this room open, when other breakout rooms have closed?

Later in the day we need 4 additional rooms, but only auto assign attendees to three of the rooms. Is this possible or do all rooms have to use the same assigning method. What happens if I auto assign to three rooms, then open a fourth - does anyone go into that room?

Thank you in advance for your help,

Barbara