I say it'd be a great idea because then we have more test subjects for those personality dialysis tests we're doing. ;]

My primary set of Agents is currently a trio - Cassie, Nat and Kelvin - but as far as I'm aware, most Agent teams are in pairs.

Back in the golden days of the PPC, i.e. before the LOTR movies came out, I've heard that Agents used to go around in threes quite regularly. However, the influx of badfic once the first LOTR film was released meant that there just weren't enough Agent teams to deal with it all, so the groupings were reduced to pairs. And, of course, there are Agents who don't have partners at all because of the understaffing.

And I've always had the image of most Response Centres being set up to only hold two Agents. My trio doesn't have so much of a problem, because Kelvin's an Elf and therefore doesn't actually need sleep as such. He's willing enough to kick back on the sofa and rest there.

you could try to put in more. It would be interesting to see how many agents you can fit into a room before they start killing each other.

I'm guessing not that many, though. Badfic tends to eat at a person's sociability, and makes them more likely to try to kill random people even without being crowded in a room.