It's hard to get a group off the ground and running successfully, but basically if you have a good idea (and it appears you have) send grams and leave messages at others homes who you think will be interested in joining with your group concept. Then you and your new members can have loads of fun creating the boards together and coming up with ideas. (brainstorming is always a great way to form group ideas here)

I'm already in one Geisha group myself, Floating World, and it's planning a semi revival soon so I can't make any distinct promises myself. But I do love the Geishas *L*

The best of luck to you, and remember, for a wide variety of reasons if you do create a group, groups have a much better chance of survival if you have more than one group leader and promote members to editor (at least 3 positions). That way others can maintain your group if your real life gets too busy to accomodate.