Everyone will talk behind each others’ backs. My advice is to not take part in any of this.
Gossip itself is poisonous. The more you do it, the more likely it is someone will eventually find out what you think of them, and that bridge is now burned. You’ll never be true friends with that person until the issue is directly addressed, and usually it never is.
It is possible to change people’s minds using gossip, but it’s tricky to accomplish. This is separate from taking part in the day-to-day leisurely gossip, where people are just chatting to pass the time. This would be more deliberate.
If you’re dealing with someone who isn’t doing their job properly, gossip with them about someone else who isn’t doing their job properly. This allows you to have an entire conversation about proper job procedures, while never actually directly confronting them. This is a passive method, almost guaranteed to not cause strife between the person you are trying to shape into a better worker.
“The person who tells lies gets caught; the person who spreads rumors is ruined. … Smart people know how to hold their tongue; their grandeur is to forgive and forget.” – Solomon the Wise