Authenticate second login automatically


We are developing a solution for a client that requires us to achieve the following.

The client has a financial application that will make use of Auth0 for authentication. The financial application allows us to embed our own custom page as an iframe into the financial applications portal, to allow us to display custom content to investors after they have signed in.

Does anyone know if we can automatically authenticate our custom page after the user has signed into the financial application the first time.

The reason we need to authenticate our second page is to query the user ID currently logged in so that we can query the financial systems API for further details.

Is this something that Auth0 can help us achieve?