Hi Dani, for rating purposes you need to look at Section 548A of the Act. This spells out the criteria that allows councils to aggregate the values for rating purposes. It might be worth while looking at the property files to see if there are applications on file. There should be some record as to why the aggregations were done as it should be requested by the ratepayer. Also check your Council policy register and confirm what is in place for your council and if there is no existing policy then create one for future use.
When you are checking any applications processed under Section 548A(1)(a)&(b) note that this is an “and” test not either or for (a) and (b).
There is also some goon information in previous enquiries under this topic in the current and historic forums. Just click in the archive at the top of the forum page to get back.
Hope this assists you and good luck.
John