Guarding is a huge issue. My Pebbles is a guarder and although she never goes after the other two she does show guarding behaviors. Is your male neutered? That would be my very first priority. My suggestion would be to find a really good trainer and begin working with him. Don't let him have free access to toys and make him work for his toys. Work with treats and him allowing you to take toys away without guarding. First your female first and make him sit, stay and work for that bowl of food. Do not free feed. It will only continue to turn even more into a problem if you do not put an end to it immediately. Pebbles guarding started at about the same age and we have been dealing with this ever since.
Good luck!