Creating a Social Sorority

[Ashamai]

I have a very tight knit group of friends that spans the nation. Recently several of these ladies approached me about making us OFFICIAL and starting a sorority. I realize this will be a purely social and community service based sorority (which we do naturally as an outgrowth of our friendship...however we want to make it more formal) , however I have no idea on how to go about starting one. I've seen some of the posts on here, but I have yet to find specific information on the web on how to go about doing this.

Specific questions I have include: is there some national society or database or association that we must first request permission from, or set ourselves up with? How does one go about incorporating rituals, rules and traditions from scratch? Are there certain things that MUST be included in order to be considered legitimate and serious?

Thanks for your help guys in advance!