1. Go to Email > eCards.
  2. Click on the eCard Reports tab.
  3. Select the eCard Senders Report. It creates one record for each sender for all selected campaigns. You can use this report to create a Group for senders.
  4. Download the report results.
  5. Reconfigure the resulting csv file into an upload.
  6. Upload the file so that the constituents are added to a group.
Alternatively, you can query on interactions in the Query tool. However, the eCards cannot always be differentiated by subject.