One approach would be to implement an observer pattern in your server. Each
client would be responsible for registering with the server, and the servant
would deliver the messages back to the client. For a client to receive the
message, it must implement a callback object, which basically makes each client
a CORBA server.
A second approach would utilize the CORBA Event or Notification Service. Rather
than register for messages with the server, each client would register as a
client with the Event/Notification Service as a push consumer. The servant would
register as a push supplier (publisher), and publish messages directly to the
event channel. The event channel decouples the publish and the consumer, i.e.
Mediator pattern. The advantage of this approach is that your servant is
not responsible for managing the subscription list.