Aqui está um método.
SELECT DISTINCT key, id, link
FROM the_table
START WITH id = 'AA'
CONNECT BY id = 'MASTER' and link = PRIOR link and 'AA' = PRIOR ID
SELECT DISTINCT key, id, link
FROM the_table
START WITH id = 'AA'
CONNECT BY id = 'MASTER' and link = PRIOR link and 'AA' = PRIOR ID