Demolay is a Masonic brotherhood for young men. They have an auxillary group associated with them called "sorority" (what it is called now in Washington) or "sweethearts" (what it was called when I was around
). I believe to be a member of the auxillary group (which from my understanding is mostly to help with the service projects and meet the boys) you have to be a member of one of the Masonic groups for young women, either Rainbow for Girls or Job's Daughters. Those are more sorority like then Demolay "sorority". There is ritual, officers, service/philanthropy, and chapters everywhere.
I was a member of Rainbow, and am a member of Eastern Star (an adult Masonic Group). If you have any questions I would be glad to try and answer them.