How can I limit data access for sales reps in Shopify?

Is it possible, within Shopify, or with an APP to limit a sales rep or employee’s access to data. I am interested in ONLY letting the rep see/access his or her ‘book of business’ ; where they would NOT be able to see customer data from other reps or the Company at large. Please help solve this dilemma

HI I am not sure I have solution for this, but what entails the “Book of Business” for said staff / sales rep?