Combo-box hide "0" value

Hi

I have created a dashboard where I am mapping salesperson in a combo-box with respect to a particular project.I'm showning the data MTD & YTD wise

So the formula what I have applied is =IF($BV$9=1,BQ12,IF($BV$9=2,CC12," ")).

Now BV9 is the cell where I have mapped by radio button.

         BQ12 is my MTD wise webi report

         CC12 is my YTD webi report.

Now my issue is when I select MTD in my radio button and when I select my project from listbox.I get my salesperson for MTD but I also get buffer value.

I want to avoid this 0 to be displayed in my Listbox