This is called "barbering" and I think it's fairly common. My rabbit China did it to her partner Rocket before she was spayed - have your rabbits been neutered? If not, doing so will probably help and is good for their health and wellbeing anyway.
Sorry that's not that much advice but I don't know much else - I'm sure some others will come along with some more suggestions shortly!
Welcome to the forum, by the way! :lol: :wave:
AMETHYST