When someone begins sharing negative second-hand information about another believer, you must stop the conversation.
Most Christians simply don't have the backbone to ether stop the conversation or extricate themselves from it.
You're not accountable to the speaker, you're accountable to the One who says you should not participate in gossip. The problem is, gossip is so interesting. In fact, just hearing the words, "did you hear about Susie's marriage breaking up?" makes the flesh quiver and tingle with the desire to hear all about it.
I have often preached about this matter. Years ago I walked in on a conversation in my home. Two women in the church were talking and when I came in the room, one of them turned to me and said "We don't like "so-and-so". I suppose I should not have been surprised, but these were women who had both been in years of my Bible studies. I held up my palm to them and immediately left the room.
We are so often unaware of our vulnerabilities and fall into the enemy's cleverly placed traps.
Gossip is a terrible, terrible thing. God's Word is abundantly clear. The problem is, we are not aware of these things until we take them to prayer. The Indwelling Holy Spirit is quick to nudge the Soldier of The Cross and alert him or her.
You have told the Lord He could have all of you for anything He wants. You have told Him you want to be changed.
That means you are going to be held to the standard you long for. Listening to gossip is like drinking from a sewer. It causes contagious infection..
Take this matter to the Lord and learn to be discerning and obedient.
Ask to see what is really happening, and ask to learn to obey in this area.