Hospital units

I am trying to apply to hospital jobs around the area. However, it's pretty tricky when the websites don't tell me what the units are like. For example St. Vincent's and the Baptist Health System. I'm just curious who to call or contact to learn more about the units. How do I find who the nursing recruiter is for example? I wanted my job applications to have tailored cover letters to the units but I'm having trouble when I can't find out what the med-surg (for example) units are like. Do any of ya'll have a particular strategy for getting your cover letters together when you don't have connections with the hospitals? I don't want to write "To whom it may concern" and have my application immediately thrown into the trash. Unless people have had success this way? Thanks!