Guidance for client -> profession -> specialty relationships?

[TysonB]

Once again, being a newbie (mostly self taught) database person, I'm having some relationship problems....

What my bosses are looking for is the following:

Client can be 1 of 3 professions (Medical, Other Health, Other)

Medical client can be 1 of many specializations

Other Health can be 1 of many specializations

Other Health Specialization can be 1 of many subspecialties

Other can be either picked from a list or entered if it doesn't exist.

So far, I have

Client Table

Client Key - unique key for each client

And I don't really know where to go from here, if I want to make the choices mutually exclusive (ie, a client who is a Medical profession MUST be a medical specialization). Otherwise, I could just do it with a bunch of different value lists.

Thanks in advance for any guidance anyone can provide me with...