Look up multiple results but ignore duplicates

OK. I had a go at it, using this array formula.

Formula:

=IFERROR(INDEX('Product Roadmap'!$B$7:$B$1107, SMALL(IF(('Component Roadmap'!$A$3='Product Roadmap'!$A$7:$A$1107)*(COUNTIF('Component Roadmap'!$A$3:A3, 'Product Roadmap'!$B$7:$B$1107)=0), ROW('Product Roadmap'!$A$7:$A$1107)-MIN(ROW('Product Roadmap'!$A$7:$A$1107))+1, ""), 1)),"")

Array Formulae are a little different from ordinary formulas in that they MUST be confirmed by pressing CTRL+SHIFT+ENTER to activate the array, not just ENTER.

You will know the array is active when you see curly braces { } appear around the outside of your formula. If you do not CTRL+SHIFT+ENTER you will (almost always) get an error message or an incorrect answer. Press F2 on that cell and try again.

Don't type the curly braces yourself - it won't work...

take a look and let me know....