I don't think i can get to that information. I don't have any way to access group invitations except to go through the actual group.
What I can do, is see if I can disable the email that tells a user when their invitation has been rescinded.
After further checking, here is what happens.
YOu go to manage members and go to the open invitations. If you click on the "Delete" button, you should see something like this:
Make sure you deselect the box that says "send notification" before you select "Yes-delete it". (Click on the image to see it larger). This will prevent the email from being sent out. Once it is deleted from the group, i am not sure we can go back and find who these are.
Yup, I didn't take the opportunity to note and un-check the box about sending of notification.
I wasn't sure if the system had a log file of sent notification messages that would detail the deleted invitations.