Applying for multiple jobs within the same company

So there's a company I've had a job alert email on for a few months. Just recently they've opened up about 3 positions im interested in. 2 I'm definitely qualified for, one I'm slightly under qualified. Is it bad to apply for all 3 or should I just pick one and hope for the best?

usa jobs
usa jobs resume
usa hotel jobs
usajobs
usa jobs federal government
usa job in ksa
usa jobs
usa jobs login
usa jobs gov
usajobs.gov
www.usajobs.gov
usajobs.com
usajobs
usajobs.gov official