You might not want all of your LDAP users to access WorldServer. To mark your LDAP users as WorldServer users, from the LDAP side, add an additional LDAP attribute to mark WorldServer users. For example, you could add an attribute: worldserver_user=true.
Next configure worldserver_user=true as an additional filter on the WorldServer side. This will allow only the users with this extra attribute set to true on LDAP side to login to WorldServer.