We are turning an old huge bathroom into two smaller baths.
All of the supply need to be replaced in the house. It is mess of copper to galvanized to Pvc and back.
How do I run the water so that I won't get an interuption of pressure in the shower when other water is turned on in the house?
The two showers will be four feet from each other and will be used at the same time. They are about 20 to 25 feet from the water heater.

We have a family of seven and have to keep the water very hot to have enough for everyone. I just don't want anyone scalded or chilled out of the shower if water is turned on in another part of the house.