In my spreadsheet BC17:BC158 is a dropdown list with a chose of HB, or Blank cell.

In order for HB to be a valid selection they need to have selected Yes from a dropdown list in cell B17,D17 or F17 or any combination of "Yes" in those cells.

If not I would like an error message box to appear stating that they must first select Yes in on of the cells B17,D17,F17.

I also will need to use this synario on other column and row commbinations.