Sounds simple.. but is it?

Okay,

What i would like to do, is this.

When someone clicks a city on my website, and then clicks a category, i want them to be taken to that page of search results under that city and category.

I hope I haven’t confused anybody.. but is this really and truly possible.. but without making child themes?

say for example… http://www.sitename.com.au/city1/

then when they click the category, it adds on /category2/

so say, http://www.sitename.com.au/city1/category2/

like a mini domain forwarding for cities and categories.. or something like that, or even it sets the city as default after you click another category, when you click a new city, it resets to that city as default.. then when they go about choosing any category, it directs them to the category but.. under that city still?

Is there anyone out there that can help me out with this one?

Thanks!!!