Clearing a check box range

Hi,

I have many checkboxes in column A in sections (a9:a15, a20:a30), when selected it puts a True/False in Column B. I have the following code which clears all True values to False. Does anyone have any ideas on how I can add a range to this?

Sub Clrcheck()
Dim cb As CheckBox
For Each cb In ActiveSheet.CheckBoxes
    cb.Value = False
Next cb
End Sub

Thanks