I need to size several pumps which all tie-in to a common forcemain. I have calculations to determine loss associated with each pump's individual flow. However, how do I account for a pump which is pumping into the forcemain downstream of the farthest pump (which will have a flow and pressure)? I am concerned that the calcs do not reflect, for the closest pump, and pressure associated with pumping into the forcemain which will be pressurized. Thanks for any direction you can give me.