Cycling in Tuscany (Italy): Any great group rides?

Hey all...

A couple of questions for the group. I'm going to be in Tuscany, Italy (Panzano to be exact),
mid-June next year for a little over a week. I've ridden there before but have had a hard time
finding organized rides/groups to ride with based out of bike stores or otherwise. Last year, I
found a good group that leave out of Florence every Sat, Sun, Tue and Thurs and does a good
aggressive ride. So, my questions are:

- Does anyone know of any other good, competitive rides in the area?
- Is it possible to sign up for a Gran Fondo without having a local club sponsor me?

I'm a competitive cyclist from San Francisco who raced for 8 years in my 20's and is still in very
good shape...so I'm looking for hard core rides.

Thanks for any help you can provide!

JT