Instead of a truth spell, which is a form of commanding spell that you would have to do on your various targets, i think an easier (perhaps) approach would be a stop-gossip/protection spell.
Google the terms "stop gossip spell" and i'm sure you'll come up with something. Alternatively search on the Lucky Mojo website. Hoodoo is full of anti-gossip spells. I'm sure you'll find something archived there/