A couple of real estate web pages carry the following:
Stratum title is a combination of stratum and company titles. An owner will hold the strata title for the portion of the land that is theirs, while a company title would cover any land that is shared, which would be part-owned by each individual in the group.
I have to say I am none the wiser. If there is a portion of the property that is considered strata, then you would think the default rules of strata would apply. But that is a guess. Stratum in Victoria feels like a different planet to me, so I hope another reader can offer better advice than I can.