Best Practice For Grouped/Bundled Item Special(Promotion) Price

[otheriz]

Dear Bagisto,

I want to have a special(promotion) price for grouped item, for example :
[Item A]-$20, [Item B]-$20 and [Item C]-$20 (total $60) grouped/bundled into 1 grouped items..

According to bagisto way..i need to create one [Item D] to be a grouped item for those 3 items
what is the best way to put the promotion price [Item D]-$50.

Should i create a Catalog Rule or Cart Rule.. ?

For Catalog Rule, if i set the condition => "SKU" to [Item D] || Action => fixed($10) discount..will it achieve the above promotion price ?

And For Cart Rule, Which i need to set the condition ? (SKU or SKU Parent Only or SKU Children Only)

Please Advice..because there's no scenario example for each condition on
https://bagisto.com/en/how-to-set-catalog-rules-in-bagisto/ and
https://devdocs.bagisto.com/cart_rule.html