multiple selection & if values match, show me the list belonging

Yes! To change the (up to 3 fields) that you see in any drop-down, navigate to table that drop-down represents. (in our case "Projects") and click "Settings", then "Advanced Settings".

Look for the section called "Identifying Records" and you'll see 3 dropdown. If all you want to display is the product name, choose this in "Column 1" and set the other two to empty, or rather the "Select a Field" option, like below...Then click Save.



Good luck!