While not specific to humanoids, the Crusader cleric variant in Dragon Mag 311 on page 51 has an ability called "Turn Foe's Followers" where they can turn or destroy worshipers of a deific foe. The Deific Foe ability is gained at 1st, 5th, and every 5 levels after just like a ranger's Favored Enemy, and basically the cleric just chooses any deity opposed to her own.