Mixed Occupancies

Can a hospital have several classifications of types of care in the same building?

Yes.  According to the 2000 NFPA 101® Life Safety Code®:

Section 18.1.2 Mixed Occupancies
Section 18.1.2.1*
Sections of health care facilities shall be permitted to be classified as other occupancies, provided that they meet all of the following conditions:
(1) They are not intended to serve health care occupants for purposes of housing, treatment, or customary access by patients incapable of self-preservation.
(2) They are separated from areas of health care occupancies by construction having a fire resistance rating of not less than 2 hours.