Parents and children
If your customer has more than one organization, you can reflect the hierarchy using parent and children customers.
The parent customer sits at the top of the hierarchy and the children are arranged below it. A customer is considered a parent if it has children or if it is not a child itself. A child customer can't be the parent of another child customer.
The maximum number of child customers that you can assign to a single parent customer is 999.
Exemptions
The parent can pass on their exemptions to their children. This is optional and can be set up when an exemption is added by clicking the box next to Apply Exemption to Children.
A parent or a child can also have their own exemptions. You can create an individual exemption for the child that is not connected to the other children or the parent. You can also create an exemption for the parent that is not passed down to its children.
When assigning a customer to an existing parent, if the child customer has an exemption that's identical to an exemption that it will inherit from the parent customer, you'll have to merge the two exemptions to save the child customer. If you choose not to merge the exemptions, you won't be able to save the customer.
Something similar happens when you mark an exemption as inherited when converting from a certificate. If a child of the parent has a duplicate exemption, you'll be prompted to merge the two exemptions. If you choose not to merge, the exemption will not be converted.
Email notifications
The parents can receive notifications about their children's exemption statuses. Read this article for more information on setting this up.