GUI event handling for individual widgets

I would like to have it so that when I right-click on a specific instance of
a control, specifically, either a list or a outline, I get a popup menu.
I've read the event-handling help page and looked at the tutorial examples,
but there is just some missing information I need to figure out how this
works.

For example, for the list widget, according to the docs, I'm supposed to
capture WM_RBUTTONDOWN for the widget's window after subclassing it.  But I
only want to do this for one instance of the control (or two, or five, but
not all of them).   Is there a way I associate a function with a particular
instance of a control, or a way I can programmatically ensure that it only
gets called for that particular instance of the widget?  

For the outline widget, I need to do something similar, in that I need to
set up a mouse-right-down event for the widget's window...but again, only
for one instance of the widget, not for the whole class.

I would just create real subclasses of these widgets, but then I lose all of
the functionality of the IDE with windows with these widgets in them.  And I
would still have the problem of associating behavior based on other events
to a individual control.

Is what I am talking about possible, and if so does anyone have any good
examples?
David