[Steven Zahm]

@ ottomek

Actually I think categories would be the best way to manage it. Use four parents with the options as children. Your site remind me of this one:

https://sscit.org/

The advanced search for therapists is based on categories. This advanced search is a solution I can provide you at a reasonable fee which would include installation and configuration. Let me know if you interested in it by contacting me using the Contact link at the very bottom of the page.

Hope that helps!