[Javascript] Checkbox Focus

[David Hannum]

Here's an interesting one.  I'm generating a list of checkboxes dynamically.
Now, the catcher is this.  While all of the checkboxes have the same name,
they are divided into three groups.  The first group is one box which has
the value equal to a comma delimited list of all the other checkbox values
in the the first and second groups.  The second group is a separate checkbox
for each of the values found in the first group.  The third group is one box
with a comma delimited list of separate values.  Now, here is what I need.
A)  If the user clicks the group one box, I need all boxes in groups two and
three to clear.
B)  If the user clicks any box or boxes in group two, I need the group one
box and the group three box to clear.
C)  If the user clicks the group three box, I need all boxes in group one
and two to clear.

I have it working for group one and two.  But incorporating the third option
is out of my league.  Any help would be greatly appreciated.

Kind Regards,
Dave Hannum