Courtesy Coburg Historical Society. It's described as the Coburg Ladies' Rifle Club and dated 1906. Miss A. Wood (3rd from left in back row) and Miss E. Wood (sitting on left in front row) and their mother Alice Wood (ran the local Red Cross Branch) were very involved in patriotic activities in the Coburg area. The sisters' four brothers served - Carlyle, Charles, Stanley and Edwin. You can read more about them here. And there is more on Mrs Wood's patriotic activities here.
I'd be very happy to hear from anyone who can identify Mrs Warren. Likewise anyone who knows anything more about the Coburg Women's Rifle Club or any of its members.