SSO Federated Auth: can we use two IDPs?

Summary:We are implementing a new Partner host site ( NewPartnerSite ) which will SSO into CPQ. Issue is NewPartnerSite partners will need to access simultaneously with our soon-to-be departing Partner Host, OldPartnerSite

How can NewPartnerSite and OldPartnerSite co-exist for this transitions period, say three weeks?

Is this possible using Federated Authentication?

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Version: 23D Patch 5

Code Snippet (add any code snippets that support your topic, if applicable):

the controlling site-wide configuration piece is at Admin , Single Sign On, Federated Authentication. Here we can enter:

--SAML Identity Provider URL