Southern California covers a vast area and a whole bunch of different terrain. Do you want the coast? Do you want the desert areas? Do you want the inland mountains? Do you want to be near a particular city or attraction? Do you want very rustic or full services? Also, what do you consider group camping? Is it just getting a site for each rig with maybe a common area or are you looking for a communal type setting? How many people/rigs? Kid friendly or adult only? Finally, pricing is going to be all over the map, are there budget considerations? Not sure many people are going to be able to be able to directly answer your question, but if you give some more details it will be a lot easier for people to begin to point you in the right direction.
