COGS for Kitting (Sales BOM)

Dear CO gurus

I have kitting parts.

But this is not assembly work, just shipping together.

So, I plan to use Sales BOM without production order.

Kitting part is just text item and no cost.

Inventory and cost is managed by each component.

In this case, I think Sales will be recognized for Parts A(Parent part).

But COGS will be recognized for Parts B and C(Child part).

So, I may wonder how gross profit is managed for Parts A?

Yoshi