I want to drag a selection box around a group of cells in one column
(a5..a10) for example and then when the right-click is pressed give the user
the option to click "Process" and then iterate through each cell entry in the
range.

How do I do that? I 've got a fair idea for the right-click thing but I'm
not sure how to step through each cell in the range and process the numbers.

Thanks for any help
Paul