Simulate Structural concrete floor between two floors for energy sim

Hi everyone!

I would like to ask, if there is a two-storey house, I will make two boxes in Rhino (which are the two zones) How can i model the concrete structure between the two zones or which is the most efficient way in order to get a valid energy simulation? Or is it enough to put the two boxes on top of each other and just adjust the floor thickness and material?