Imagine a business selling candys. They have an article group called “A Kilo Of Sweetness”. The group contain inside article like Gummy Bears, Lollipops, Candy Canes, and so on. Now we can order this article group and select 4 Gummy Bears (400 Grams), 2 Lollipops (200 Grams), and 4 Candy Canes (400 Grams). In total we ordered 1 Kilo of candies, but we decided the quantity of each article based on our preferences.