issue with graph

Hello all

having some trouble.

i have a stacked side bar graph that im having trouble with showing a certain "city" appear in a different color.

I have attached a sample workbook.

basically, i have 2 main series (total sales and average sales for different cities).
-that comes out great on a graph

however, i made series 3 and series 4 to showcase only a single city, so on the graph, when the user selects from the drop down menu *highlighted in yellow*, that particular city stands out in red or something? hope you follow.


been struggling really bad so i would apprecaite if someone can help me with this issue!

thx you so much!!!

cheers