Modyifying code or new to delete duplicate items in others comboboxes based on combobox

Hello
I want adjusting this jindon's code or new whatever . what I look for when I select the item from first combobox then shouldn't show the the same item in the others comboboxes , for instance if I select item ATR-100 from combobox1 then should not show in others comboboxes and and if I select item ATR-101 from combobox2 then should not show in comboboxes 1,3,4 . so when select the item from specific combobox shouldn't show in the others comboboxes .
thanks