Physics says yes. And at the US Patent Office, it certainly looks like the answer is yes, according to (at least) this US patent application. The abstract reads:
A process for separating O$_2$ from air, that includes the steps effecting an increase in pressure of an air stream, magnetically concentrating O$_2$ in one portion of the pressurized air stream, the one portion then being an oxygen rich stream, and there being another portion of the air stream being an oxygen lean stream, compressing the oxygen rich stream and removing water and carbon dioxide therefrom, to provide a resultant stream, and cryogenically separating said resultant stream into a concentrated oxygen stream and a waste stream.
I would say the yes is conditional in that you'd probably need a room that is sealed from communication with the atmosphere (otherwise equilibrium will be re-established with respect to oxygen pretty quickly), is vented to the outside in order to dispose of the oxygen, houses one heck of a strong magnet, and has a strongly-locked door to prevent the unfortunate organisms from leaving.