Using the Contact "When Records Merged" Workflow Integration Event

Hi -

Looking for advice on Using the Contact "When Records Merged" Workflow Integration Event.

We are hoping to use that workflow trigger but a bit confused by the integration message that results. We intend to use the Merge function when we find two contacts that are duplicated, to merge them to the one primary contact and delete the duplicate. Then, the hope was that the Integration Event would send the merged Primary Contact ID and the Duplicate Contact ID in the integration event so that our downstream systems could replace any reference to the Duplicate Contact ID with the Primary Contact ID.