If you implement  your servers  with Session Beans and Entity beans, they can help you very much. you can use a Session Bean for decision making about getting
obtating value objects  from local  entries or from other server  session bean!

But i f you have problem  about use EJB Techniques you can use this pattern with you RMI Server. So you Required one DataAccess Controller whic speaks with you clients. This controller is resposible to getting Data from Local Database or from Another Server by calling and RMI call to it.either the data obtained from Local Database or Remote Server it must be delivered as a Value object  ( See Value Object or Data Transfer Object patterns)

you can define a unique interface for client  to Server and Server to Server Calling. because when a Server asks another server it's like that a Client calls Its local server!


It can be even implemented by a Web Service if you can use Apache Tomact and AXIS toolkit. if you use web services then more client application can use your server services. such as Delphi based Application or .Net Application. It's more scalable!!!