I'm having an issue where I'm getting multiple Subscribers in my 'All Subscribers' list with the same email (same person) but different subscriber ids because I'm using Salesforce reports and Journey Builder to send emails to both Leads and Contacts. I have a set of nurturing emails that go out to Leads in a Journey, then follow up sales appointment emails that go out regularly through a scheduled automation to Salesforce Contacts, which means a subscriber that starts as a Lead then converts and receives a follow up email will be duplicated in my 'All Subscribers' list.
I would prefer not to switch my subscriber key to email because that just makes it more difficult to read/write data from Salesforce. Should I script detecting duplicates and deleting the earlier version? I think I would lose all the engagement data from the earlier Subscriber, is there a merge function?