You can configure an enterprise server so that the catalog itself is accessed via Fileshare.
In ES Admin, on the Edit page for the server, on the JES tab, include the name of the Fileshare server in the path for the System Catalog.
This also causes the spool files to be accessed via Fileshare.
Changes made on this page are picked up when you next start the enterprise server.
In the real world you would probably not put system files such as the catalog under the control of Fileshare, since accesses to these are managed by enterprise server and it would not bring any advantage, just the additional overhead of Fileshare communications.