I think some of the technique might have to do with keeping track of what the conversation, as a whole, actually is about. The Star Trek bridge scenes, with characters waiting their turn with information, works well because the conversation is about advancing the plot, and we never leave that even with the addition of new speakers. I think my question would be, between all these people you have--four, right?--how many conversations are
actually going on? It's been said that three people actually triple the potential for conflict from two, because instead of one relationship to think about, you have three--A/B, A/C, B/C.
Four makes it even more complicated.
I had to write a scene awhile back, with
six individual characters all having a confrontation. Half the characters were strangers to the other half, which technically made it one argument, with three people on each side. But the lines of conversation became really complicated because, while the first person was arguing with the three strangers, the second was giving him casual support but mostly arguing with
him whenever a particular grievance came up. The third was more or less on the side of the first but
answering the second, while basically ignoring the three strangers. The three strangers themselves were all trying to make the same argument, but they weren't working together--one of them was trying to make the point more belligerently, and the other two were more-or-less allied in peaceful negotiation but only one of them resented the first's interference.
I'm not sure I actually succeeded in making the scene flow right--but I learned a few ways of thinking about conversations from that. There was one main conversation going on, primarily between two people with occasional support when a couple of the others had a relevant thought. That was carrying all the rest. All the rest, when they happened, had the feel almost of parenthetical dialogue, and they weren't technically what the scene was about--they broke in, briefly, and then we returned to the main conversation. The question was, how long could I spend on a side conversation before returning to the main one--and could I go from the main conversation, interject a side conversation, and then interject
another side conversation into that one, before returning to the main one? A simplified example might be:
Robbie swung around to face the Swordmaster. "You're very brave with a sword in your hand," he said. "But what about face to face with another blade?"
"Blades don't have faces," said Bailey, under his breath.
"Should I regard that as a challenge?" asked the Swordmaster.
"
Robbie...." said Nellie and Bailey together.
Robbie grinned at his two companions. "Hey, I'll be fine. I'm not totally incompetent, you know."
They stared at him. Nellie couldn't tell if he was serious or not.
The Swordmaster smiled, glancing over his shoulder. "Sophie, give me our son's sword."
"So that's where it went," Maxie muttered.
"You left it by the lake," said Sophie, tossing the blade to her husband....
And so forth. I think that was five characters speaking in total, or six if you count the combined dialogue at the beginning (I know, cheating!), and the perspective is Nellie's. It's an extremely abridged version of part of the actual conversation I wrote. Everyone's got a different agenda, and they're pursuing it subordinate to who is actually doing the action--I suppose, if the situation is social, it would be whoever's doing most of the talking. It's different if there's only one conversation, and the entire six people trying to take part. I've typically found that real-life conversations between that many people either split up into multiple individual and
simultaneous conversations, or everyone (primarily) listens to one or two people--or possibly a third--who are having one single conversation, and they interject from time to time when they feel they have something relevant to say. There's a social hierarchy involved in who gets to speak, and when. It all depends on how strong everyone's separate agendas are. And what the conversation is about.
This might be the longest post I've written so far. Six-person conversations are complicated things!