Note 7 defines, ate least according to the Yad Hachazaka, exactly what is “chavra chavrach ees ley:” Only when you have no intentions of spreading the news then if it just comes up in conversation, the nature of the world seems to be that it will be repeated from person to person. The news will just keep on rolling for a long time. However when one wants to intentionally spread some juicy info and he makes announcements and tries publicising to as many people as quickly as possible then the news will get out there but wil not stay out there for a long time and when eventually dissipate, this is considered outright lashon hara and does not fit the category of “chavra chavrach ees lei.”
Note 8 mentions an argument between the Chofetz Chaim and the Yad Hachazaka on why a person who heard this piece of news with at least two other people can repeat under the proper circumstances quoting who he heard it from. The Yad HaChazaka says you can quote who you heard this info from because the fact he said it in a group of at least 3 intimated that he doesn’t care if he is quoted. (Which means there could be situations where he would care and you can’t quote him.) But the Chofetz Chaim says the reason why he can be quoted is because everyone is going to know by who and what was said any way since it was said b’apei tlasa. However the Chofetz Chaim warns everyone that this shouldn’t be a reason to loosely allow you to speak lashon hara because the chances of all the parameters of apei tlasa being met is very farfetch so one should be very cautios!
Halacha 4 says that even if one of the at 3 people who heard it repeats it, the 3rd party who hears it cannot repeat it, he knows everyone heard about it, because who says it is true and if it can be confirmed that the first person heard it correctly who says he actually heard it with at east two other people. The obvious question we raised was how then does news ever spread? The answer is that there is a concept in Shas that everyone transgresses the laws of lashon hara at some point, at least avak lashon hara (quasy lashon hara which applies by the rules of apei tlasa) therefore because of the unfortunate reality of life whether it is right or not word spreads and repeating it over and over again can potentially become permissible, though as we said earlier it is usually highly unlikely.