Dear Ms. Sutton,
Thank you for posting your request on History Hub!
We suggest that you review NARA’s web page on how to find and research Mexican Border Crossing Records.
And based on the dates in question, we suggest that you request a copy of their Alien Files (A-Files) by submitting FOIAs to USCIS (www.uscis.gov/g-639) for each individual.
We hope this is helpful. Best of luck with your family research!