two-way communication between EJBs in different applications

[Robert Ren]

Hi,
Is there anybody had the experience to use EJB A in App 1 to call EJB B in
App 2, as long as EJB C in App 2 to call EJB D in App 1. The half of the
solution is to use the parent attribute in application tag ( one-way), but I
also need another half to form a two-way communication.
I tried to parent each other, but failed. I tried to use RMI, but it did not
work either.
Any suggestion will be highly appreciated!


Robert Ren