I have these three units within 5 feet of eachother. The place where the bathroom vents to is the only place within reach to have a penetration to outside.
My options are to stack these three exhausts, or up the size, add some backflow preventers, combine them, or something else that you guys might know.
Also, I'm concerned the dryer vent may form a vapor trap or some sort, but I don't know enough about it to figure that out.