Discount on products from certain categories?

Question

WordPress

I have a wordpress wokomers.
There was a need for such a task.
We have - many categories of goods.
It is necessary to compile a set/set of 6 products (let's call it PRODUCT-SET) from products from certain 6 (six) categories, and only in THAT case (if the set contains products from these 6 categories) then
a discount is provided for the PRODUCT-SET, .. .. but
.... these six products are not specific products (they may be different - but each from its own category)....
.... i.e. , in the PRODUCT-SET card, you need to provide the ability to select a specific product from its category - by type of variation.

All this is like a computer designer.
e.g.
We have product categories 1-chassis 2-memory 3-video cards
in the GOODS-SET, the client himself chooses the case, then the memory, then the video card, and so on.
and components, respectively, are pulled from the general catalog of goods.
I hope I explained clearly, thanks.