How long have you had the kittens? They will keep weeing if they can still smell their scent so you need to clean the area thoroughly with an enzyme based cleaner. Can you keep them out of the bedroom for now?
If they're new kittens it could be a stress thing as its new surroundings for them but I agree with others that a trip to the vets is in order as they can check for crystals in the wee, make sure it's not cystitis which can be dangerous for cats.