Example of a "xenforo to [anything]" bridge where xenforo is the 'slave'

[swiftlytilting]

I've been tasked with creating a bridge where Xenforo is the "slave" to a Mediawiki database, basically the opposite of the existing MW-to-XF bridge. We have users already signed up for MW and need to give them access to Xenforo without requiring them to create and maintain a second account. ideally we would like to also use the permissions from MW to define user permissions in XF.

I was wondering if there were any existing add-ons which utilize this technique? or any tutorials on modifying how the authentication system works in xenforo?