Dear John,
I think you are looking for "one login" implementation, where the user authenticates to the Microsoft Domain and then has SSO to SuccessFactors directly. You can achieve this with two SAP products:
- SAP Single Sign-On (as mentioned also by Yuksel AKCINAR)
- SAP Cloud Identity service.
SuccessFactors support SAML technology and in your current setup users are requested to authenticate to the SAML Identity provider that is currently setup (according to your explanation) to work with the domain credentials. You can achieve "one login" if your SAML Identity Provider offers Kerberos/SPNego authentication. This is available with SAP Single Sign-On and SAP Cloud Identiy solutions. I can organize a presentation for you and your team to explain the capabilities and to discuss your scenario. If you are interested just drop me a message on donka.dimitrova at sap.com.
Regards,
Donka Dimitrova