Multiple job postings for same unit...do I apply to each job number?

I am a recent graduate and am hoping someone who has worked in HR or Nurse recruitment could give me some advice. If there are multiple positions posted for the same unit but with different job posting numbers (ex. Staff Nurse -0001, 0002, 0003, and 0004) Should an applicant only apply to one of the postings? Do the applications all go to the same place if they're for the same unit or are they sequestered by job number? I don't want to annoy recruiters, but I also don't want to miss out on opportunities because I applied to the wrong number posting. Thanks!