what dictates that the right association is A - A - 21 instead of B - B - 21 ?
If you know that, then you might be able to join this query to the underlying table and use the answer to that question as a rule/join or criteria in another query. It may take more than 1 additional table along with this query - impossible to say without understanding the relationships. Based on your last comment, you could also consider following up your append with an update, based on that same rule. Sometimes you just have to do things in multiple steps.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.