B2C SSO Sign-in: How to identify customer domain within Appian.

We're using Azure B2C SAML based application with Identity provider-initiated flow. Please refer: https://docs.microsoft.com/en-us/azure/active-directory-b2c/saml-service-provider-options?pivots=b2c-custom-policy

We'll embed this identity provider-initiated flow URL to our client websites, when customers click this identity provider-initiated flow URL that will take them to the Azure B2C SSO login page.

We'd would like to know if there is any way to identify the requesting URL where the identity provider-initiated flow URL is triggered from, please? For example. when www.client1.com and www.client2.com calling this identity provider-initiated flow URL. Within Azure B2C portal OR Custom login page if there any possibilities to identify this Azure Idp initiated URL is triggered by www.client1.com OR www.client2.com.

For example, on successful sign-up, call the Appian Web API to pass the client / customer-id and sign-up email-id parameters to Appian? OR any other better approach to identify where the custom is attempting to sign-in from?

I appreciate your help. Thanks.