Pet rabbits communicate dominance within a group through various behaviors such as chin-lifting, mounting, chasing, and even nipping or biting other rabbits. Dominant rabbits often display confident body language, such as standing tall with ears erect and making themselves look bigger than submissive rabbits. They may also assert their dominance by controlling access to resources like food, water, and preferred resting spots. It's essential for rabbit owners to understand these communication cues to maintain a peaceful and harmonious bunny group.