Using Notes in Mail View

Is it possible to add an additional “pane” to the Mail screen that shows a summary of my Notes. Currently, I have Mail folders in the first column to the left, email summaries in the next column just to the right of that, body of the selected email in the next column, and finally to the far rright I’ve selected my Agenda to be visible the final column.
If a separate column cannot be created for Notes in the Mail view, alternatively, can a Note somehow be “added” to the Agenda column, or is this column just for displaying Tasks and Calendar items?

Thanks.