Můžete použít rekurzivní CTE:
WITH CTE(ITEM_VALUE, ITEM_ABOVE, DESCRIPTION, ITEM_GROUP) AS
(
SELECT ITEM_VALUE, ITEM_ABOVE, DESCRIPTION, DESCRIPTION AS ITEM_GROUP
FROM mytable
WHERE ITEM_ABOVE = 'CAR'
UNION ALL
SELECT t1.ITEM_VALUE, t1.ITEM_ABOVE, t1.DESCRIPTION, t2.ITEM_GROUP
FROM mytable t1
JOIN CTE t2 ON t1.ITEM_ABOVE = t2.ITEM_VALUE
)
SELECT ITEM_VALUE, ITEM_ABOVE, DESCRIPTION, ITEM_GROUP
FROM CTE