Boiler Feedwater Pump Controls

Boiler Feedwater Pump Controls consists of a Master Controller and a controller for each of three steam driven pumps. How do these four controllers interact with each other in terms Process Variable (PV), Set Point (SP), and Command Output (CO)? If controllers of the two pumps are changed such that their control valves operates on feedwater pressure, is manipulating the Master Controller alone good enough to control the pump left in the original setup?