User lookups in database host field



Is it possible to set the database host field of a MySQL service to a user lookup field? I’m wanting to allow different users to be hosted on different back-end databases (shared databases but have a high-performing DB, or isolated DB, for select clients). The schema of the DBs are the same. I would like the database service to use the user lookup for the hostname of the DB. I am able to use lookups for the database name and the credential, just not the host, which seems strange to me. Any idea if this will be released, or if I’m doing something wrong?