Hilchos Rechilus, chapter 2, section 3
Some say that if a person denigrated someone before three people, there is no more rechilus involved in speaking of the how he denigrated the person [because the news will spread anyway]. This needs all the requirements mentioned earlier in paragraph 14 in laws of lashon
hora. But one may not rely on this leniency in practice because many Rishonim disagree with it and forbid speaking to anyone if one’s intent is to spread the story, and certainly not to the person spoken of. Even if one has no intent to spread the story one should still not repeat the story as we wrote above in laws of lashon hora paragraph 11.