Enegryplus control for load distribution for dual boilers

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My buidling has two boilers: one electrical and another natural gas. There is a electrical demand max limit (Pmax) for the building. The control logic will be: The electricity input to the boiler should be Pmax-Pothers, and the rest of the heat is supplied by NG boilers. *Pother means the electricity consumption except the boilers. I don't know how to control the load distribution between boilers by EMS