In the display manager, add each of the option bindings to the same column. add the first option column to the display, then add the second option column and select the option to crroup with the previous column, add each of the other columns using the same group option.
when a column is set as unique, it allows that column to control whether a new line item is created for unique values.
for example, say you had a shirt with color options.
you would want the color column to be unique so that the shirt with red option selected would be a separate line item from the shirt with yellow selected.
