Authenticate user for local service provider using passport-saml with local ID provider

I have my node application, which authenticates user with Username/Password

I am trying to use passport-saml to offer SAML authentication for internal service and external services (external domain), now both passport.js with local strategy and SamlStrategy have to live together

Confused, when user directly goes to my site, he had to login using local strategy, but when service requests, it has to go through SAML, will they work together? can my SAML provider use a local ID Provider, hosted in the same service? Should not prompt user to re-authenticate if user has already logged in using local strategy

Not sure if both can exist in same node app.js or i have to separate these two