You could certainly write code - in Outlook - to process incoming messages.
This code could write things to an Excel file.

Trying to do the processing from the Excel end would be possible, but
probably a lot harder.

I haven't written Outlook code, and don't know its peculiarities (aka object
model), but it's got VBA just like Excel has. I don't know if there are any
Outlook programming groups. You could start with the Office group, MSO -
http://www.freelists.org/webpage/mso.