Bridge table

There may be a better way to do this, but here is what I did:

- Duplicate one of your queries (Edit Query -> right click the query from the list on the left and click "duplicate")

- Right click on the column header and select "Remove Other Columns"

- If there are null / missing values, click the small arrow on the right side of the column header and click "Remove Empty"

- Right click on the column header and select "Remove Duplicates"

That gives you a unique list to use as the bridge.

Then define two relationships, a many to one from 'Created by' to the bridge, and a one to many from the bridge to 'Sold by'.  Make sure both relationships are set to filter in both directions, and you should be good to go!