(a) The Under Secretary for Health shall determine the manner in which personnel are to be selected for training in the Centers. Preference shall be given to career personnel of the Administration.

(b) To the extent that facilities are available medical and health personnel from outside the Administration may, on a reimbursable basis, be provided training in the Centers. Such reimbursement may include reciprocal training of personnel of the Administration provided under sharing arrangements entered into by the Under Secretary for Health and the heads of the entities providing such reciprocal training. Any amounts received by the United States as reimbursement under this subsection shall be credited to the applicable Department medical appropriation account.