How to create a calculator for the cost of a weighted product in an online grocery store on 1C-Bitrix?

Question

1C-Bitrix

There are 2 types of goods: "piece" goods with a fixed weight and "weight" goods, in which the weight "floats".
On the site, in the product card, you must:
- for piece goods, indicate the cost of 1 piece in rubles;
- for weighted goods, indicate the price for 1 kg of goods and display the approximate cost of 1 piece in rubles.
For example, the average weight of fish is 2.0 kg, and the price of 1 kg of fish is 650 rubles. It is necessary that the cost of 1 fish equal to 2 x 650 = 1300 rubles is displayed in the product card.
When setting up the exchange of 1C and BUS, only the price for 1 kg is transferred to the product card on the site, and the site does not correctly display the cost of a unit of goods. Who knows with what standard means of 1C or BUS to make the desired scenario work?