One possibility is to create a storytelling meetup group on meetup.com. A LOT of people are on it, and if there isn't a group in their area that matches their interests, it will notify them if one is created. Once people join online, you start organizing real-life get-togethers using the built-in calendar functions of the website.
There are groups of every kind on there. A LOT of the mothers in our area use meetup groups to create and maintain real-life playdate groups, for example.