How to hide header column in Matrix visual.

Thank  You  for your help. Now I am able to  construct the Matrix of monthly sales against top 10  customers along with Other customer. Also at the last column it needs a conditional formatting of showing last column values in different background colour for which I have created one DAX function and  in condiitonal formatting I  set Format Style as Field and  the field is my DAX function and applied on Values only. By this setup my objective become fulfilled.  

But now I have one question i.e.  Now one reqirement I got  that before Customer field one Index column needs to be incorporated mark 1 to 10  for top 10 customer. But When I put the index into row area it is showing index value but Other customer case is not accomplished. Is there any  way  to  do ?