As customers associate more domains to Amazon WorkLink, we’ve learned that it is common for their domains to use authorization flows from different identity providers. To enable access to even more content, Amazon WorkLink now allows customers to add website authorization flows from multiple identity providers in their account.

from Recent Announcements https://aws.amazon.com/about-aws/whats-new/2019/05/announcing-amazon-workLink-support-for-additional-website-authorization-providers/