Three 75 gallon water heaters tandem

[siklife]

Hello everyone, Im hoping someone can help me out here. I was asked to install 3 Bradford White 75 gallon power vent water heaters (big house). All the rough was completed by another plumber. The house is pretty much all finished, all thats left is Trim and installing these 3 water heaters. The house is not zoned so these water heaters will have to be installed connected to each other. What would be the best way of going about this? The water heaters will have a circulating pump. Also any advice on what circulating pump and expansion tank id need for such a setup would be appreciated ! Thanks in advance