I want to run a simulation for a selected zone in a buliding by E+. The target zone is set specific geometric info, but the rest zones of different floors are gathered into one big zone due to unknown geometric info. Does this kind of design for Non-target zones influence the accuracy of target zone simulation?

P.S: The HVAC system of building is created by mutil VRFs(outdoor units/indoor units). The target zone has its own outdoor unit and indoor units ,which have no relationship with that of Non-target zones.