Teenager blues

My 5 orphans are in their adolescent years and they are being mean to my oldest cat - Joji. Joji can't even go to the litterbox without being teased by one of the youngsters. She prefers to be alone and never been friendly to other cats but she has been tolerant and sometimes kind to the brats when they were kittens. Should I keep her apart from the terrible 5 until they "grow up"? Or let Joji handle it? I have been scolding the meanies and it seems to help a little. Is my interfering the best way to go?
BTW, because Joji was adopted as an adult, I don't know how old she is but she may be going on 15 or more. Thanks.

I would keep her seperated.

If you don't separate her more or put out 2-3 extra litter pans, they will cause her to start peeing in other places because she cannot be at peace to use the one you have.

Oooooh, I know how you feel here. My mom's kitties, Porthos, Athos & Aramis are like this. All three are brothers but Porthos & Aramis pick on Athos all the time. Mind you, Athos is kinda dumb (sorry Athos! I love you anyways!) but he got so freaked out he finally started using my mother's bread basked (on the kitchen counter) as his litter box.

The solution was to allow Athos to have his own room at night and while they were gone from the house. Athos has his own bed, his own litter box, etc. With the door closed he can pee & poop in peace!

Okay, thank you!