Cats like to be up high, hence why your counter is so attractive to them. I've only got one cat who constantly gets on the counters, Gabby. I've given up trying to keep her off. I wipe them down before I prepare any food on them and she knows not to jump up while I'm working there.
Try giving them some cat trees with platforms (not those tiny little two foot tall ones), they can lie on in a room adjoining the kitchen, that might help too.