Is there a way to group the output of a query based on two rows
SELECT MAX(co.[slsman])               AS Salesman, 
       MAX(co.[cust_num])             AS "Customer Number", 
       MAX(ca.NAME)                   AS "Customer name", 
       co.[co_num]                    AS "Customer Order", 
       ci.item                        AS item, 
       MAX(ca.curr_code)              AS curr_code, 
       SUM(ci.price * ci.qty_ordered) AS sum_value 
FROM   [co] co 
       LEFT JOIN custaddr ca 
              ON co.cust_num = ca.cust_num 
                 AND co.cust_seq = ca.cust_seq 
       LEFT JOIN coitem ci 
              ON co.co_num = ci.co_num 
WHERE  co.co_num LIKE 's%' 
       AND co.stat = 'o' 
       AND co.cust_seq = '1' 
       AND item NOT LIKE '%carriage%' 
       AND ci.stat NOT LIKE 'f' 
       AND ci.stat NOT LIKE 'c' 
GROUP BY  co.co_num,
          ci.item
ORDER  BY Salesman, 
          "Customer Number"