This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
This can be difficult and can probably best be done by some proprietary application server feature. For instance, the app server may be able to pin the singleton to a specific server instance in the cluster.
A better question would be: What are you trying to achieve?