External MS SQL Conect

I have one project where:
- school system working with MS SQL DB
- tables with teachers, students and parents data
I need show some data from these DB in my Joomla 3.7.2 website but i need integrate ACL School system in my Joomla. Is it possible?
The school system have login data (username and password(not Crypto)) and i need use these information and syncronize with joomla users.
Any sugestion to make this happen?
thanks in advance

Kazuo