what i would try doing is,find a toy they like to play IE A feather on a string or something they like doing.use it as kinda of a bribe,Let them play IE jump and chase and pet them and praise them alot when they catch the feather in their mouth.Just use it as a special time thing.I think after a week or so just make it short play times so they know they have to enjoy it while they can.I am sure the mean kitty will come out and go away for the most part,if they get mean put the feather straight away and say bad kitty or BK.Let them know "they have to be good"to play.Or use a sponge ball or what ever they like to play with..its worth a shot..

Hootch