Answer:
vertical consolidation.
Explanation:
Vertical consolidation is a process used by companies to increase their control on construction and distribution of a product.
In vertical consolidation there is usually purchase of firms up or down the supply chain.
In this scenario your friends buy a salon from a couple, and then buy a shampoo company that they use to supply the saloon product at lower cost. This is an example of vertical consolidation where your friends are obtaining more control in distribution big shampoo.
