Dynamic Dropdown menu

Hi.
Hope you are doing well?
I’m busy building a website for an estate agency. I have attached 2 pictures so that you can have a look at what I am planning to do and have done so far.
You will see that in the ‘FinnishedPage.jpg’ picture is the search functionality of what I’m planning to do. It has 5 options:
1. Province – Dropdown with 9 provinces – Provinces stored in Database(dropdown comes from database – did it with ‘select list’).
2. City – Dropdown with Main City of each province except 1 Province that has 2 cities – Cities stored in database.
3. Area of City/Suburb – Only one of the cities has ‘Area of City/Suburb’ which is also stored in the database.
4. Price – Stored in database.
5. Property Type – Stored in database.
How the above is supposed to work is: When the visitor chooses a province from the ‘province’ dropdown menu – that province’s main city is supposed to appear in the ‘City’ dropdown menu. So there is one city called Pretoria – if that city is chosen certain ‘Area of City/Suburb’ of that one city is supposed to appear in the ‘Area of City/Suburb’ menu.
Because what is is that I want to do is once they have chosen on the search menu it must search the database for the Property that the client has put in.
I went through one of the Dynamic dropdown tutorials – So what I saw was that the Dynamic dropdown only has the Parent Child option. Is there another way for me that will be applicable to what I want to use?
Thank you for your assistance.
Daniel.