I understand you are asking if these people can be held accountable for speaking of you in such a manner that you were not offered a job. My question comes in contemplating how difficult would it be to prove in a court of law that this happened? Obviously, the other parties would deny the allegation, and it would be he said/she said. I can't see this becoming a productive lawsuit.
On the other hand, if the prospective employer that didn't hire you enjoys this type of illicit gossip and hurtful unfounded rhetoric, maybe they weren't the kind of employer you wanted to work for in the first place?
Just a thought....
Good luck to you. I hope this works out.