At the moment that is going to require two separate installs of dbFront because SSO mode is naturally an exclusive option.
When SSO is enabled then dbFront won't show a login screen. If dbFront encounters a user that needs authentication it will redirect that user to the configured SSO provider. It is the SSO provider's responsibility to authenticate the user and then return them to dbFront.
It is possible to update dbFront so that it could provide a different authentication option depending on the URL, but that has not been implemented at this point.
