What functionality do you need in your green room?

Relatively easy to achieve an audio-only version using a single audio bus.

There are more complex versions if you also want video (requires use of one output) and/or independent producer TalkBack (requires a second audio bus).

You need to do a bit more than this, but yes this is the general idea.

I mean, you'd need to make and put something on the video output & add the guest audio to the greenroom bus (both of which I thought were a given), but I can't think of anything else that'd need to be done, nor do I do anything else.

It's a script that takes maybe 10-15 minutes to write, and almost all that time is getting the code to add or remove people on the video output multiview.

Of course, it's a bit different if you want to send everyone a special greenroom without their own video being sent back to them on a delay (which I always find preferable) but when you have more than 2 callers, that's impossible with only 4 outputs. And with only 2 callers, having 2 separate outputs isn't all that more complex than just having one, because you no longer need to fiddle around with adding/removing callers on a multiview.

If you plan far enough ahead and think things out, you don't even need to use complex scripting to figure out where people are in the multiview, because you'll already know. Same goes for if you're taking them all out of the greenroom at once.

In those cases, or if you aren't putting callers' video in the greenroom at all, it's 1 or 2 basic web scripts (depending on what all you need to do) that can be knocked out in less than half that time.

Use a dynamic input and you can use the same script for every caller instead of needing 1 per.