DOAS with Packaged Rooftop Air Conditioner - WA State Energy Code

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The Washington Energy Code for 2015 has a new prescriptive requirement for providing ventilation via Dedicated Outside Air System (DOAS). http://www.energy.wsu.edu/BuildingEff...

Section 407 of this code defines the baseline or standard HVAC system - for an air-cooled condenser it's packaged rooftop air conditioner unit, with a footnote clarifying that spaces must receive ventilation air through a separate DOAS system. From what I understand, EnergyPlus and OpenStudio are unable to model thermal zones which are connected to more than one air-loop. In that case, it's impossible to model both a central DOAS system with recirculating packaged rooftop air conditioner both connected to a zone in EnergyPlus. Does anyone have a solution to this modeling issue?