Will it be suitable if I forward you the SOBI pro database of the listings (sql format - almost 50 entries) so that you can check if the required is possible with your module.
The category tree is as follows:
Category---Subcategory--2nd Sub Category.
The listing will be under the 2nd sub category.
So on the search page, the user will select :
State (Category)----> City (Sub caegory)
>locality(2nd sub category)
On selecting the locality the listing under that will be shown.