How to simulate a subsystem by EnergyPlus

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I would like to simulate a part of HVAC system (i.e. subsystem) such as;

1. Heat source subsystem, including chillers/heatpumps and chilled water pumps
2. Condenser water subsystem, including chillers, condenser water pumps, and cooling towers, and
3. Air distribution subsystem, including VAVs/CAVs and AHUs/FCUs.

The purpose is to understand how the subsystems work and to investigate the system characteristics against some changes in boundary conditions and control parameters as BESTEST does. Thus, my question is how to input boundary conditions (cooling/heating load and/or flow rate or temperature) to separate the subsystems.

I know that LoadProfile:Plant can be one of the solutions, but it seems that it can only be used for heat source subsystems.

Is there any way to simulate subsystems by EnergyPlus?