I have a product with different weights. But I want to categorise them as one and total up the weight for sale of the product. Salmon1 : Salmon 150g ; Salmon2 : Salmon 300g; Salmon 3: Salmon1 (weight) plus Salmon2 (weight);

I want to use Salmon3 as a product to be put for sale by grams.

Is there anyway I can do it using BOM or any modules I can download to accomplish this? Thanks.