Can't get enough of ''The O.C.''? Neither can Fox, for whom the drama was the only new scripted hit this season. Variety reports that Fox is enlisting ''O.C.'' creator Josh Schwartz to create a ''companion series'' (don't call it a spinoff, those involved in the deal say) for next season. No details were available about the new show, but Variety says it's likely to continue the ''O.C.'''s generational mix of teen and adult characters while skewing slightly older. In other words, it would be the ''Melrose Place'' to the original show's ''Beverly Hills 90210.'' Schwartz would write only the pilot while continuing to serve as the executive producer on ''The O.C.'' Look for the series to debut in January.