I'm setting up a nationwide job hunter site, where potential employers can search for job hunters by location (states) or by field of expertise (occupation).

However I don't want to list all the states and occupations in one long list under Categories.

But I want the potential employers to be able to select an occupation, for example, Accountants nationwide or Accountants California. Or simply all candidates from all occupations in, for example, Nevada.

Can you offer suggestions on how to set this up in the simplest, least confusing way, with Categories? Thanks.