I don't care too much honestly, so please go ahead, yet I wonder if "it makes it convenient to import the geometry from GRB" is the best argument.  The naming from the different "Hallen" for me is an indicator that they are different buildings (for instance, at https://inventaris.onroerenderfgoed.be/erfgoedobjecten/200270 you can read that the "Tussenhal" was added later).  After all, you don't map two adjacent houses as a single building neither, right?
This being said, I think there is no real right or wrong here, so if you want to go ahead, please do so!