When defining a HWS system, outlet pressure can be specified at the System Marker:
and an additional pressure drop can be defined at the outlet:
If the outlet is connected directly into Flow and Return pipes, then this additional outlet pressure is considered when the circulating pump is sized.
The system should be drawn with single flow pipes connecting the main to the outlets. This mimics how a real world system would function, and precludes the pressure drop at the outlet being included when sizing the circulation pump.
The sample projects used to generate this article can be downloaded from here.