I think you are referring to principal and alternate nomination method. This method provides for designation of a principal nominee by the member of Congress. The other nine unranked nominees are submitted to the academy for evaluation and compete as alternates. If the principal is fully qualified (academics, medical and physical aptitude), he or she will be appointed and will fill the vacancy.
Note that this method does not take into account the quality of the other nominees if the principal nominee is fully qualified. On the other hand, if the principal does not qualify, the alternates then compete for the vacancy. Selection at this point is based on merit as determined by the evaluation and ranking of the alternates by the Academy.