Set passcode + no waiting room on PMI, waiting room + no passcode generally?

[Andy3142]

I have Zoom Pro. I'd like that my PMI meetings have a passcode and no waiting room, while my non-PMI meetings have no passcode and have a waiting room.

And I'd like this without having to change anything in the zoom.com settings before any meeting.

Under zoom.com settings it looks like I can independently choose Meeting passcode yes/no and PMI passcode yes/no, but I can't apparently set Meeting waiting room YES and separately PMI waiting room NO.

Inside the meeting under Participants > 3 dots overflow > I can set "Enable waiting room" to NO but I'm not clear how this interacts with zoom.com settings. For example unless there is a passcode, surely I can't disable the waiting room at all? Or, is this the magic answer to my quest, and what I should do is

(a) enable waiting rooms in Zoom.com,

(b) in Zoom.com enable passcodes for PMI but not for regular meetings and then

(c) arrive at my PMI meeting early and set "Enable waiting room" to NO?

If that is the case then I don't understand how all that interacts with letting participants Arrive Before Host, because it needs the host to arrive first.

Thanks in advance for your help.