There are a few things I've done in the past. Sometimes they work, sometimes they don't.
- Don't let them know that it bothers you. If they can't get to you, eventually, many of them will stop.
- Kill them with kindness. Guilt trip them. If they are truly rotten people (which is totally possible) it won't phase them, but those with even just a bit of common decency and empathy will feel guilty and might eventually stop.
- Confront them indirectly or directly. Last ditch effort unless you can pull it off while keeping your cool (I'm not very good at this one)
Finally, document, document, document and if necessary go to a manager. I had one situation where I went through all of the above. I finally got results when I told my supervisor that if it didn't stop I was going to look for other work. She didn't want me to leave so she said she'd handle it. It did stop finally. I still work with one of them and don't trust her at all, never will.