Clearly gossip is a sin, whether done by saints or by preachers talking about one another. However, even in this instance, it should be by ministers in a formal, closed-door session. It should not be information that is shared with the laity. Pastors must always be on guard to build, not destroy, confidence in the ministry.
Preachers can cer tainly be guilty of gossiping about one another.
However, I have not observed this to be a big problem in our ministry circles. Still, we should be aware of a couple of precautions. For instance, our conversations must be aimed at being a positive effect on individuals. If Sister Smith in the local church has cut her hair, this is not something that needs to be advertised. Talking about her does not help her to mature in the Lord nor dissuade her from her actions.