send a messase to a known window

[Horrid]

I have an IE tool band object, and I can find all instances of the band using enumwindow, but how do I send a message to all those windows to tell them than an event has occured on one that they should all replicate?

I was going to use sendmessage but how do I capture the event at the other end? I tried windowproc but it didn't like me doing
if uMsg = "logout".
The message will be something like "logout" or "updatelist".

Thanks, I'm sure its just somethings I overlooked