Interprocess Communication (X11-Client --> X11-=Client)

[kcox at onebox.com]

Hello,
    I have a somewhat difficult question (at least for me). I am trying to send characters to an X11 client process without that process being in focus. For example:

X11 Clients:
1: Small dumb program running in ATerm
2: An intance of Eterm.   

How do I get the program in ATerm to output characters in the Eterm window?
My first thought was to start sending keystrokes to the X11 server. However those keystrokes will only get dumped into the window that is in focus.  Any remotely close ideas are dutifly appreciated.   If I'm barking on the wrong list please let me know.


kieran