One schema per different databases

Good day.

Continuing the subject about DB cluster based on plproxy - a question for developers:

Is it possible to manage schema visibility from one database for different databases, at least in the read-only mode ? For example as schema pg_catalog.
Or is it possible to create FDW on the "shared memory level" for solving this task ?
Method of solution based on the external connection via FDW/dblink is not suitable for high traffic projects.

--
Regards