Marty,
You hit on a big topic with me. except I'm not really ready to tell all just yet ,more exploring to do.
We have them here on Ambergris and Its really part of the same system.
did you read this:
# IF YOU DIVE IN A CAVE, BE SURE TO HAVE THE PROPER EQUIPMENT AND TRAINING
# IF YOU ARE AN OPEN WATER DIVER AND WISH TO GO ON A GUIDED TOUR OF ANY CAVERN AREAS MAKE SURE YOUR GUIDE IS A DIVEMASTER AND FULL CAVE CERTIFIED. ONCE AGAIN, ASK TO SEE HIS OR HER GREEN CARD ISSUED FROM THE REGIONAL SAFETY OFFICER.
# I DO NOT ADVOCATE FOR ANYONE TO GO CAVE DIVING. IF YOU CHOOSE TO DIVE IN UNDERWATER CAVES YOU MUST TAKE FULL RESPONSIBILITY FOR ALL CONSEQUENCES. REMEMBER IT'S YOUR LIFE!
# REPEAT: I DIDN'T TELL YOU TO GO CAVE DIVING.
We don't have any qualified tour guides as yet but it can happen.

White Sands Dive Shop
https://whitesandsdiveshop.com/