Add a new user role called ‘Wholesale,’ ‘Trade,’ or something similar, and assign it the appropriate privileges. Your wholesale users may have a single role or multiple roles.
Once you have created a wholesale user role, you may add your trade clients as WordPress users. The use of your new role is entirely up to you. It is possible, for example, to charge a variety of fees for this job using the Dynamic Pricing plugin. Using the WooCommerce Password Protected Categories plugin, you may also establish private categories that are only accessible to wholesale users.