Trouble in paradise

A couple of days ago I discovered some liquid on the floor in the kitchen.  At the time, I had no idea what it was, I just cleaned it up (I have a really messy husband.)  Yesterday there was another puddle in the hallway by the deacon's bench and this time I identified it as cat pee.  This morning there was poop on the spare bed (covered with 3 pee pads, thank you very much).  An assumption on my part is Sassy not allowing Sadie into the cat box again, trapping her in the bedroom.  Too much poop for Sassy, she poops and pees small - Sadie makes much bigger messes.  We washed the pads and closed the spare bedroom door closing off Sadie's favorite window.  Carl is off buying more Ace Hardware plastic spray bottles, the last two he purchased require several pumps to get water to spray, Sassy hears the pumps and runs before the water ever comes out of the bottle.  The Ace bottle however, has instant water which gets her every time she runs at Sadie and we're watching.  So, we're going to place them all over the house, close off the bedrooms and keep at Sassy until she stops tormenting Sadie.  She's turning Sadie into a neurotic cat and we just don't know what to do about it anymore.  I hate the idea of locking one of them up.  If they don't interact, they will never learn to get along.  I don't care if they never become friends as long as they quit using the house as a big litter box.  Sassy now uses the litter box in the living room the most so we can't lock Sadie up there and deny the box to Sassy.  We tried that on vacation and Sassy pooped everywhere.  Sadie never uses the bathroom litter box so I'm afraid to lock Sassy up in the living room and let Sadie poop where she wants to.  Other than spending every second with them, I've run out of ideas.  The experts say to distract the cats when it looks like there might be a problem, but I truly believe you could blow an air horn in Sassy's ear and she won't even hear it - when she's fixated on Sadie, she cannot be distracted in any way except for the water spray.  So, from now on, she's going to be one wet cat.