Our website is using DocCheck, an external authentication provider, to authenticate and identify contacts. We use the DocCheck ID, which comes as the request parameter "uniquekey", as contact identifier, so that the contact, when logging in on another device, can be re-identified. These users are then authenticated in Sitecore via a virtual user.
In addition to that, we're planning an own user management with registration, login etc. The users will be logged in via email address and password. The email address should now be used as another identifier to identify the contacts loggin in with these credentials.
The users should then be able to use both DocCheck and our own login for different parts of our website, so that we have DocCheck contacts and our own users.
Is it possible to combine these two identifiers to identify as one contact?
Thank you and kind regards