Same-sex pairing is not out of the question, but requires at least one submissive rabbit in the group and a little more patience on your part. It is considerably easier if BOTH rabbits in the pairing have been fixed. In fact, you may not be successful with the match if they are not. This behavior should dissipate the longer they are fixed. Although the average length of time until most rabbits are pretty well bonded is about one week, we have seen rabbits take as little as one afternoon or as long as many months to become friends.
Neutral territory is imperative.
Beginning the bonding in a small, neutral territory is vital to this relationship working out. DO NOT put them in a cage together until they have been getting along perfectly for several days. If a serious fight breaks out in a cage, it is generally difficult to separate them. Although these behaviors may look similar to you, they are all very different and it is important to recognize the different ways rabbits speak. Fighting is usually an instantly, purposely vicious attack.