joinform and search modification

There should be four dropdown fields at the joinform, each one depending on the one before.
First “Country”, second will be “Province”, third one should be “City” and the last field should be “University”.
So depending on the choice of the field, the other fields should only show the data according to that country , etc.

For better understanding, if the users selects AUSTRIA, at the next field there will be listed only all provinces of Austria after choosing LOWER AUSTRIA for example, only all cities in lower austria could be selected and so on.
If no country is selected, the following fields should be empty or with a hint to tell the user to select one line above.

For the search function, it should work exactly in the same way. The people should be able to search for people according to universities by using the same hierarchy. Each field depending on the one abov.

So that was the function, now to the rest, the fields should be modifiable over the admin panel, as the other panels are. So adding citie or universities whatever should be done over admin panel.
Very important is, that I dont need the modification made by you. Just the code, because after updates it should be easy to reintegrate it by myself.

I need a high quality modification, to make clear that there are no problems with any other mods.

If there are any questions left, please let me know.