WITH t AS
(
SELECT 'A' c1, 'X' c2, 'X' c3, 'X' c4, 'X' c5, 500 c6 FROM dual
UNION ALL SELECT 'B', 'X', 'X', 'X', 'X',  500 FROM dual
UNION ALL SELECT 'C', 'X', 'X', 'X', 'X',  500 FROM dual
UNION ALL SELECT 'D', 'X', 'O', 'X', 'X', 1000 FROM dual
UNION ALL SELECT 'E', 'X', 'O', 'X', 'X', 1000 FROM dual
UNION ALL SELECT 'F', 'X', 'X', 'O', 'X', 2000 FROM dual
UNION ALL SELECT 'G', 'X', 'X', 'X', 'O', 2000 FROM dual
UNION ALL SELECT 'H', 'X', 'X', 'X', 'X',  500 FROM dual
UNION ALL SELECT 'I', 'X', 'X', 'X', 'X',  500 FROM dual
)
SELECT MIN(c1) || DECODE(COUNT(*), 1, '', '~'||MAX(c1)) c1
     , c2, c3, c4, c5, c6
  FROM (SELECT c1, c2, c3, c4, c5, c6
             , ROW_NUMBER() OVER(ORDER BY c1) rn1
             , ROW_NUMBER() OVER(PARTITION BY c2, c3, c4, c5, c6
                                 ORDER BY c1) rn2
          FROM t
        )
 GROUP BY c2, c3, c4, c5, c6, rn1-rn2
 ORDER BY MIN(rn1)
;