An Oracle Names server can be configured to administer more than one domain.
To specify multiple domains:
In the navigator pane, expand Oracle Net Configuration > Oracle Names Servers.
Select the Oracle Names server.
From the list in the right pane, select Configure Server.
Select the Domains tab.
Enter the domain name in the Domain Name field and time-to-live information, and then choose Add.
Repeat step 5 for each additional domain.
Choose File > Save Network Configuration.