Dependent Droplist IF Selected Format Phone Number Accordingly

I have a series of dependent drop lists and a cell which asks for a phone number. I would like if the selection in the previous cell is North America, the format of (111) 111-1111 is chosen. if the user enters the improper format I would like them to be prompt with an error "Improper Format - <Proper Format>", clear contents, and re-select the cell otherwise if valid select the next cell. It would need to strip out the leading 1 incase an international code is entered and also special characters such as "(",")","-","+","_" as well as spaces.

The next problem is that it would have to change format to if another selection is chosen. The other two selections are Australia and Europe. Europe is more difficult of a format as the area codes vary in length. I will be dealing predominantly with Sweden whose area codes even vary. For Australia I would like it to be in the format 011 61 1 1111 1111 where 011 61 will be added even if the user does not enter it (or if not possible prompt with proper format).

The cell asking which continent is G35 and options are "","Australia", "Europe", "North America"

The cell asking for a phone number is K47

The next cell on valid response is G50