Let me throw a totally different idea:
Rent a very large house, # of bedrooms depends on how many people confirm, somewhere in France - maybe around Lyon or Aix en Provence; everybody stays in the same house and then you celebrate your birthday in the house; saturday trip to the local market, one group goes to buy the booze, another the food, bring your own music, cook dinner at home and enjoy a good time with the people you like.
October may still be nice enough in Provence so you can enjoy a pool.
Sunday AM look for a nice bistro for "brunch" and then everybody leaves at their own leisure.