For an email segmentation project, I'm finding that I might have to associate donor attributes with now-deleted contacts. Here is an example (with a real CID for reference).
Donor 5011493 was sent an email during Big English. This CID has now been deleted and associated donor attributes are tied to CID 1618203. To complicate things, the email address associated with 5011493, which received this email back during the campaign, is not the primary email address for CID 1618203.
I would want to know things about this contact which are kept in the silverpop_export table: their largest donation, first donation date, etc. so that I would be able to determine what donor segment criteria they would have fallen into in past years had we segmented emails in 2018 (for example).
Is there any way I can associate these two CIDs or their associated email addresses together? I would like to be able to pick up CID 5011493 from a send in civicrm.civicrm_mailing_provider_data and associate it with attributes in silverpop.silverpop_export_staging or wmf_donor - if this is possible.