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How to relate two tables with the key to a third table?
In Referral (key Record ID), there is a field called Referring Contact - which is a key for the table Contact. In Activity (key Record ID), there is a field called Activity Contact - which is a key ...
You create a Summary field in the Contact table from the Activity table to get the Maximum Record ID of the Activity related to the Contact.
The next thing is you make relationship from Activity to the Contacts table (the red one) and use that Summary field as the Reference. Do NOT let it create a new field.
Then you make Member Name from Activity a look up field in Contacts through that Relationship.
Now every Contact will show the Member Name for the very last Activity created.
