how to communication between BHO.

[darwinye]

HI,
how to communication between BHO.
I am writing a Browser helper object and need communication between
the BHO instance.
For example, In my BHO ,user can enable/disable the BHO's a function.
If currently the user opened
3 Internet explorer and disabled the BHO's function in one of IE, how
can I change the state of the other two BHOs.

1. Maybe I can use window's message ,but I have to know the other BHO
window's handle? I dont think this would be
a good idea.
2. Or through shared memory, but it is dangerous?
3. Or postmessage with HWND_BROADCAST,but this message only can be
posted to "disabled or invisible unowned windows, overlapped windows,
and pop-up windows. The message is not posted to child windows."

So do you have any idea to help me ,any help would be appreciated.

Thank you very much!