Alright, this is a case that requires that both databases allow access for the same user via external authentication,
With SAP HANA that's not doable in the very same way.
However, even on MS SQL Server this wouldn't be a clever way to do it because you hard code the server and db name for the remote schema in your application code.
That makes it much less reusable and introduces dependencies to the external landscape naming.
To avoid that you'd rather create a synonym to reference the external DB.
HANA virtual tables provide basically the same functionality here.