"select" only if theres a same record in the table

i have two tables A and B. relation is one to many for A. i want to select from A only if there are more than two records of A in table B and also checking some condition in table B. if the question's not very clear please let me know.

Substitute A_PK for whatever A's PK is and try the following:

SELECT *
FROM A
WHERE EXISTS
(SELECT B.A_PK
FROM B
WHERE B.A_PK = A.A_PK
GROUP BY B.A_PK
HAVING COUNT(*) >= 2)