My advice is to pray about it, seek God's word on it, then attack with vigor, as God directs. In reality we who have been pastors know that the pulpit is the WORST place to address a besetting sin, and from what you stated, this may be a multi-generational sin pattern that stems back to the founding of the town.
Can you band together with other Bible-believing pastors and covenant to pray about this sin that has the small town, and its environs in its grip? Dealing with it one church at a time is a sure-fire way to loose the battle, and some in your congregation.( Been there, done that.) However, if other believing pastors agree, and attack the problem as God directs them to do, then you all will be a powerful force in the community, and make substantial progress in this.
I recommend reading together as pastors Neil Andersson's Bondage Breakers
and research to see what the history of the town reveals as a ground of authority for this prevailing, besetting community sin.
One way that you could do it--if God so directs you-- is to use ju jitsu, and flip the gossip into an IMMEDIATE prayer request. Because gossip sometimes is a way to make the gossiper feel superior, placing the gossiper into the role of a pleader for the person she/he wants to malign will make the person think twice about repeating gossip in your presence.
Before I forget. is your wife a partner in the gossip or is she equally grieved by it? Is she is a partner, then you first need to deal with your private church before you do anything with the church you pastor.
Hope this helps!
Father in heaven, I pray for this pastor, and his justified hatred of the harm that gossip is doing to the flock that you gave him to shepherd. May you give him all the cunning of a fox, the tenacity of a she bear in protecting her cubs and the gentleness of a lamb as he deals with those in his congregation and yes, even his household, May he find support from other similarly-minded shepherds, booth in the town and in his denomination so that this will not be his to fight alone.
I ask this in the name of Jesus, our Savior, Amen