If your double wall cavity is truly a corridor and is occupiable space included in ventilation calculations and having its own air terminals,
then you will want it to be modeled as its own thermal zone.
If this is not occupiable space, you may be making the model unnecessarily complex by modeling the cavity as a separate zone.
I would suggest looking into the WindowProperty:AirflowControl & WindowProperty:ShadingControl to see if the options shown there represent your cavity airflow and shading. If yes then you could just model as a wall with a construction with 1.1 m air gap.
If you do end up with the cavity having its own thermal zone, and you want to pass light through this thermal zone to model daylighting sensors on the interior, you will need to model all thermal zones as convex. A formal definition of convex is that any straight line passing through the zone intercepts at most two surfaces.