Growing up, my cats ripped a cheap canvass cabinet which they used as a scratching post and as a hammock.
I have 3 boys and a mom (she is "fixed"). When two older ones started fighting, I "fixed" one. No more fighting. Now the younger one is getting into fights. Soon one of them will be fixed too.
A New year's toy horn is great with breaking up fights. These cardboard horns work every time. Works on people too.