As you probably know, in theory, it is possible to create such larger Zones using the Zone Tool, but for most purposes it will not work well since elements will have no way of knowing which Zone (the smaller or the larger Zone) to choose when generating values the Related Zone fields in Schedules, plus these smaller and larger Zones will not be aware of each other and so will not update automatically.
The only possible solution I can think of right now (besides writing your own ArchiCAD Add-On to do it) would be to use the Archicad-Grasshopper Connection. Obviously, I have not tested this, but you could create those larger Fire Zones in Archicad using Morphs, for example, then you could get the 3D geometries of those Fire Zones and the regular Zones into Grasshopper using the AC-GH Connection, and there are probably Grasshopper Components which would make it possible to query which Zones' 3D geometries are situated within which Fire Zone 3D geometries. Then, you could create a Property for Zones (Spaces) which would contain the Fire Zone Name or Number the Zone 3D geometry is situated in, and Grasshopper would set the value of this Property based on the results of those queries.
This would not update automatically (but Zones do not automatically update either), so if Zone/Fire Zone geometries change, you would have to rerun the same Grasshopper Visual Script to update the values of the Zone Property containing this piece of information. I hope this explanation makes sense.
FYI: There was a similar discussion recently about the IfcSpatial Zone entity that is specifically for such purposes in IFC4, unfortunately, no such feature is yet implemented in Archicad:
https://archicad-talk.graphisoft.com/vi ... 12&t=69531
The thread also resulted in a wish you might want to vote in:
https://archicad-talk.graphisoft.com/vi ... 30&t=71283