This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
Even in the case of vertical clustering, different EJB containers utilize different JVM.so EJB from one container can not access EJB from another container on same AppServer using Local Interfaces. You have to use remote interfaces.