Welcome to this board and Abantecart -
There is no direct way to do this within one cart to the best of my knowledge. However, you could investigate the multi-store setup as a way to segregate customers to certain categories. This runs off one database, and one admin panel, but each store has a unique subdomain location of the main domain OR you can have totally unique domains names. You cannot just do different dirs within the main domain.
But each store can be set to show it's own categories, own products, own pricing.
Lee