First of all, maybe you should try to get to the root of the problem intead of just trying to cover it up?
Are your dogs getting enough physical and mental stimulation daily? Most dogs that bark excessivly do it out of boredum.
why not teach them the quiet command?
Sometimes even putting the bark on cue will cut out the behaviour unless you ask for it . (I knwo people who this has worked for, and its also worked for humping behaviours too
)