If she has been in kennels a while, this can cause such behaviours because the dog gets used to peeing pretty much where it lives and doesn't have the chance to learn to go further away from their quarters.
I did some work in a kennels at Xmas and some of those dogs had obviously never lived in a home and even peed, pood in their own beds and such.
You could tell the boarding dogs from the rescues because they'd usually be a lot cleaner...often refusing to poo in their kennel area at all and waiting until they were taken to the exercise area.

It's a case of starting from scratch again like you'd teach a puppy. Perhaps a dog cage in the house for her to spend a bit of time in while she learns...I doubt she'll go in there...and regular visits to the garden to go pee. She can stay out of the cage if she has peed recently and isn't likely to need to go again anytime soon. Perhaps the use of one of those puppy pads or something which attracts them to pee on it out on the lawn or something and get her accustomed to peeing on the grass instead. Dogs are creatures of habit when it comes to toileting. Even my two don't like going to the toilet on lead...they aren't used to being on lead when they toilet. Sleet refuses point blank to go on lead and Wren isn't too keen on it.

Come up with some sort of cue for relieving herself and praise her when she does it in the right spot. Mine know what I mean when I tell them to have a poo or pee and they go do it...providing they need one.
Meanwhile, when they are at home, they need to watch for any signs of her being about to pee such as walking slowly forwards sniffing the floor.

For dogs who start peeing somewhere unusual as a result of another dog being introduced, I'd say that was more to do with stress of change. Dogs, like children, might show this sort of behaviour as a cry for help as well...where they aren't happy.