REST API Authorization for SAML logged in Users on AEM Publish servers

We have an app, where end users login to the application using SAML. Once logged in REST APIs are used. These REST APIs are hosted outside of AEM.

Is there a way can authorize the REST API calls in the external system using login-token created during SAML login ? For example,  we pass the login-token with REST API calls and the external server validates the login-token with AEM Publish instance and then provides the API response.