It can be very hard to completely litter train a rabbit that hasn’t been spayed or neutered. Other reasons that they are peeing outside of the litter box are because they are in a new place with new people and they are marking their territories, plus, rabbits like to pee on soft surfaces, such a a bed. It would be best to keep them off of the bed for now. When you first bring a rabbit home, it’s best to limit their area, and not let them roam all over those first few days. You could attach an x-pen to their cage to give them more room for play and exercise, and if they are out in the pen, that would give you an opportunity to clean out their cage and replenish their food and water, since they hopefully would exit the cage and be in the pen area.
Your rabbits will need to be separated before they are 12 weeks of age. For one thing, rabbits are often mis-sexed and it could turn out that they aren’t both female, then you are presented with a litter in a short while. Even if they are the same sex, they will need to be house separately at or before 12 weeks old. When puberty hits, aggression can come with it. If rabbits fight, they can severely injure each other. After their spay surgeries and recuperation, you can properly re-bond them.