아아 답변 감사합니다.
수정했어요~

new.php
$sql_common = " from $g4[board_new_table] a, $g4[board_table] b, $g4[group_table] c
              where a.bo_table = b.bo_table and b.gr_id = c.gr_id and b.bo_use_search = '1' and bo_list_level <= '$member[mb_level]'";
group.php
    $sql = " select bo_table, bo_subject from $g4[board_table]
              where gr_id = '$gr_id'
                and bo_use_search = '1'
                and bo_list_level <= '$member[mb_level]'
              order by bo_table ";

index.php
$sql = " select bo_table, bo_subject from $g4[board_table]
        where bo_list_level <= '$member[mb_level]' order by gr_id, bo_table ";