You may want to try this. A sling-shot. Practice up. Then use it on who ever strikes first. It's best to hide in a loft or behind a tree or trailer. The mare will soon realize when she acts out she feels pain in the rear. About an hour so should do it or maybe more.
We did this to a mare, she would not let a rather small pony eat, so my dad hid in the loft and the mare got it in the rear when she would bare her teeth at the pony. Soon the pony ruled all horses would move to let the pony eat.
Just an old cowboy solution.