How do I tell someone I am not into them without hurting their feelings or ruining out friend group?

These three guys I work with are constantly flirting with me everyday, it gets weird at times. Well anyways I only like one of them and he is the one who just got out of a relationship recently. The other two are great guys, amazing even but I'm not into them like the other guy. I just don't want to be rude and be fix this problem in the nicest way possible.
How do I tell someone I am not into them without hurting their feelings or ruining out friend group?
Post Opinion