$output = array();

        // Iterate over the main array and create a new subarray if
        // it doesn't already exist, or add to it if it does.
        foreach($raw_array as $subarr) {
            if (!isset($output[$subarr->dropdownsId])) {
                // New array indexed by sid
                $output[$subarr->dropdownsId] = array();
            }
            // Append the whole array
            $output[$subarr->dropdownsId][] = $subarr;
        }

        return $output;