I find to help with them not being noisy is to stagger the times you put them down by 10-15 minutes. My 2 amazing nappers get put down 1st as they have no problem falling asleep in the same room. Then 15 minutes later my worst napper who loves to chat at quite time, but if everyone else is asleep then they have no one to engage and will eventually fall asleep.
I have 2 others that have to lie down but they get to watch t.v or pick a movie!