Login on third party script with Xenforo credentials

[themago]

I'm not even sure if this will be possible but

I would like to try to integrate my xenforo forum with a third party script, ( https://yetishare.com )

Instead of having users register again, it would be awesome if they could login using their xenforo login, and have certain xenforo usergroups correspond to certain "account packages" on yetishare.