I agree with fun&care...I have a few that chat to each other or just to themselves for a bit in the beginning but they fall asleep within minutes. Before I leave the room I remind them all in a firm voice that there is no talking to each other. This usually stops the older ones (the 2 yo's) but the younger ones still chatter for a bit.
I will occasionally turn the walkie talkies on before leaving the room. If I hear them chatting for a long time or see that they are not sleeping, I can just walkie talkie down to the room "go to sleep xxx"...they don't know where my voice is coming from and I can see on the monitor the look of shock on their face and they instantly settle down and go to bed. It's kinda funny actually haha.
If it was affecting the others to an extreme, I would be looking for another place to put the chatter.