We are hoping to use Gitlab SaaS in future , currently I am trying to figure out how to manage student accounts.
I have been reading  and checking this forums posts beforehand, apologies if I missed something.
What we would like to do, is adding students via an invitation email to groups or projects and afterwards being able to identify them by their custom student ID (each student receives a custom ID, like bue12345, when they are enrolling at our university).
At first sight, the invitation API is exactly what we require. However looking closer,
students can freely pick their username and displayname, so we cannot reliably know who is who, which is relevant for grading etc.
Do other options exist for Gitlab SaaS in an educational context?