When my kittens were having diarrhea I would monitor their litter box activity constantly and would pick them straight up after they defecated to avoid it getting on their feet. Sometimes if it was particularly liquid I would lift them while defecating. It's a hassle, but maybe you all could do something similar right before your cat urinates, like lifting the behind up to a reasonable height and holding it there until they finish. That might train them to do it themselves. Only do this if your cat doesn't get agitated though, especially with males since you don't want them to get urination anxiety and hold it in.
