Loshon Hora: The allowance of B'apei t'lasa (in front of 3)

Question

Although they are governed by very strict limitations, there are numerous 'hetterim' for the prohibition of lashon hora, such as apei t'lasa, l'toieles, etc.

The Chofetz Chaim (Klal 2, §3 - see there for strict boundries) codifies the dispensation of apei t'lasa (a statement made in front of three people, which is considered avidi l'geluei and therefore already public):

יש אומרים, דאם אחד ספר גנות על חברו בפני שלשה, אף דהוא עבר בודאי על אסור לשון הרע וכנ"ל, אף על פי כן אם אחד מהשלשה, ששמע דבר זה, ספר אחר כך לאחרים, לא עבר בזה על אסור לשון הרע, מטעם דכיון דשלשה יודעים מזה, ממילא כבר נשמע הדבר ונודע לכל, דחברך חברא אית לה, ובדבר העשוי להתגלות לא אסרה התורה משום לשון הרע

According to some opinions, if one slandered his friend in front of three people, although he [the original slanderer] transgressed the prohibition of lashon hora, nevertheless, one of the three listeners who subsequently relates the slander to others will not transgress the prohibition, because since 3 know about it, it is already publicly released [for 'a friend has a friend etc.'], and something which is destined to be revealed was not forbidden under lashon hora.

However, the Chofetz Chaim adds a clause (§4):

ואפלו מה שהתרנו... דוקא השומע הראשון, ששמע בעצמו מה שראובן ספר על שמעון באפי תלתא {בפני שלשה}, אבל מי ששמע ממנו, אסור לילך אחר כך על סמך הזה, שאמר לו המספר לו ששמע דבר זה באפי תלתא, ולספר לאחר מהגנות ששמע על שמעון, אף אם לא יזכיר מי הוא המוציא והמביא הלעז הזה על שמעון, אם לא שכבר נתפרסם הדבר ונודע לכל

Simply put, this hetter applies only to one of the three listeners. However, although any of the three is permitted to pass it on to others, one who hears it from them may not continue to relate the story - because although if it was said b'apei t'lasa it becomes permitted, the second-generation listener has no firsthand knowledge that it was actually said b'apei t'lasa, and is not permitted to believe his friend that it was so (because he is עד אחד נגד איתחזק איסורא).

My question is:

If we are to accept that the second-generation listener may not believe it was said b'apei t'lasa, then not only would he not be permitted to transmit it further, but he would be prohibited from listening in the first place. Consequently, the first-generation listener (one of the three) should not be permitted to tell him, because he will transgress לפני עור by telling him something he is not permitted to listen to. Ergo, there is no hetter of b'apei t'lasa?

Answer 1

I'm not going to talk about the case in the question, because I don't have enough information either disprove the assumptions. However, there is another case where b'apei T'lasa is applicable:

The first man says lashon hara to three people, creating a situation of b'apei T'lasa. (This is, of course, prohibited; as mentioned in the chofetz Chaim quoted by OP). One of the three listeners can then go tell three more people the lashon hara he heard: for him it's not lashon hara, as he was one of three to hear it from the original teller. For the listeners it's also not lashon hara, as they are also a group of three, to whom applies the heter of b'apei T'lasa. Therefore, there is no 'lifnei iver' when the first listener spreads the lashon hara around, and we have a viable case of b'apei T'lasa.