@jason-johnson Using Microsoft Entra as IDP is definitively possible. ChurchTools supports Single-Sign-On via SAML, which Microsoft supports as well.
To make it work, you would need two things:
1.) a SAML SSO Client App configuration for ChurchTools in Microsoft Admin Center
2.) a SAML config in ChurchTools.
For 1.) you can do the configuration yourself (we can give you directions), for 2.) we would have to do the config for you. At the moment you cannot configure this yourself within ChurchTools.
So, if interested, please contact our support and ask for Matthias.