How can I model an air to water multipurpose heat pump in DesignBuilder??

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I'm currently modeling my project’s HVAC system in DesignBuilder, which includes one geothermal reversible heat pump and two multipurpose air-to-water heat pumps. However, I am facing several challenges in properly configuring this setup in the Detailed HVAC method:

- Modeling Multipurpose Heat Pumps Correctly:

I attempted to use Heat Pump - Heating and Heat Pump - Cooling, but I am unable to modify them to a Plant Loop EIR Heat Pump, which is specifically for air-to-water systems.

Changing the template disables all parameters, making it impossible to configure the heat pump correctly. Has anyone successfully set up a Plant Loop EIR Heat Pump in DesignBuilder, and if so, how?

- Implementing Simultaneous Heating & Cooling

The multipurpose heat pumps operate in three modes: Heating, Cooling, and Simultaneous Heating & Cooling.

While I can define heating and cooling separately, I am unsure how to model the simultaneous mode in a two-pipe fan coil system, where all terminals share the same supply water temperature.

Is there a way to configure the system to support both heating and cooling loads at the same time within the limitations of a two-pipe setup?

- Modeling the Collector (Manifold) Before Distribution

The three heat pumps supply a collector (manifold) before distributing the conditioned water to the terminal two-pipe fan coils.

In the DesignBuilder schematic, the collector is represented as Primary Heating Circuit Pumps and Chilled Water Primary Circuit Pumps, but I want to ensure that it integrates the three heat pump sources properly.

Should this be modeled using a Fluid-to-Fluid Heat Exchanger, Water Heater as a buffer, or another component?

I haven’t found any detailed examples or templates that closely match this configuration, so any guidance or shared experiences on setting up this system correctly in DesignBuilder would be greatly appreciated! Thank you in advance for your help!