Cat Scratch Fever

I'm sorry to report that Minestrone, the cat, is still not having an easy time living here. 

One of my in-laws' cats, Sasha, is old and crochety.  For whatever feline reason, she hates Minnie.  Now, the litter boxes are downstairs in the basement.  Sasha hides in the shadows, and when Minnie sneaks down the steps - Meow! Hiss! Raow!!!  Fur tufts flying up in the air, paws out, kitty Ultimate Fighting.

We tried moving one of the litter boxes up to the ground floor.  Minnie would go in there and avoid Sasha.  But then Bonita, the dog, started eating what was left in it.  Ewwww!  So we put the litter box back downstairs and this morning there was a nice surprise on the bathroom rug.  Apparently Minnie would rather go outside of the litter box than brave another round with Sasha.  The funny thing is,  Minnie has claws and Sasha doesn't.  She could kick Sasha's tail if she wasn't a pacifist.

Minnie is a lover, not a fighter.

What are we to do? This cat situation doesn't make it easier for me to feel 100% peaceful here. It doesn't help that my MIL relays every cat incident that unfolds.   Every time I hear about another battle, I feel sickened - almost as if the cats' actions reflect my own inner turmoil.