A CPA site which does yearly taxes for clients of different industry wants to target only certain group/industry. They dont want to do yearly taxes, accounting for regular public, they want business from clients like for example:- Clients who are Doctors, Attorneys, Software Professionals.

Is it possible to target only these group through SEO (without ppc/cpc)?
If so how to target only certain group?

Please advice, any suggestions, feedbacks really appreciated.