Problem:
user opened up a platform to internal clients.
One of internal client reported to be able to see the order of someone else who has nothing to do with his department.
Thus user worries that he can not guarantee the confidentiality of internal clients' orders.
Solution:
Users from the same company with "external client" profile having this access right activated :
can see all the orders from their company.
So, the solution is to turn the right off.