How can I group products on a sales quote?

Suppose a customer wants a quote for product A. When quoting for product A, we must put the price of product A but also have line items for products B, C, and D which always come with product A and must show up as separate items with their own price.

This is similar to a phantom set. (The sales quotation is for set A. The delivery slip is for the components of set A.)

What objects and mechanisms in regular OpenERP v7 could achieve this?

PS. Of course, everything is possible with deep programming.