; (B) best practices with respect to the guidelines developed in accordance with subsection (a); and (C) changes in the legal authorities, policies, and procedures described in paragraph (1)(A). (c) Sufficient staffing The Commissioner of U.S. Customs and Border Protection shall ensure that sufficient qualified child welfare professionals and qualified experts in pediatric medicine are stationed at each port of entry and each U.S. Border Patrol station with a high volume of arriving children to accomplish the duties described in this section without creating an undue delay in the length of time children and apprehended parents and legal guardians remain in the custody of the Commissioner of U.S. Customs and Border Protection. (d) Family unit tracking number (1) In general Not later than 90 days after the date of the enactment of this Act, the Secretary of Homeland Security shall submit to Congress notification that the Secretary has established a system for use by U.S. Customs and Border Protection to assign a family unit tracking number to each member of a family unit that is apprehended, including each of the following: (A) An apprehended spouse. (B) An apprehended parent or legal guardian. (C) A child accompanying an apprehended parent or legal guardian. (D) Each accompanying member of the family group, including siblings, grandparents, aunts, and uncles. (2) Requirements The Secretary of Homeland Security shall ensure that a family unit tracking number under paragraph (1)— (A) may be shared among the data systems of— (i) U.S. Customs and Border Protection; (ii) U.S. Immigration and Customs Enforcement; and (iii) the Office of Refugee Resettlement of the Department of Health and Human Services; (B) is included on any document pertaining to any member of an apprehended family unit