Jade Haunt Stacking

Couldn’t find if this has been answered and won’t be able to test it myself soon. If a friend and I are running the 2 piece set of jade. If I cast haunt on say a boss then my friend casts it, does the dmg amplify still? Or can it only be a haunt that I casted previously?

I haven’t tested this but a guess is that you need to use same rune or you will just overwrite each others haunt.