QuickBooks has the ability to create a job/sub-customer and this relationship is synced to Method:CRM as well.
However, what is a job? What is a sub-customer?
A job allows you to create a project within QuickBooks and you can track transactions specific to this job, but it is still under the main customer.
A sub-customer is similar and the example used is to imagine multiple locations/franchises for a customer. Again, you can track the transactions specific to the sub-customer.
You may be familiar with the term job or sub-customer, and you may wonder if there is a difference.
There isn't in QuickBooks Desktop. A job and a sub-customer are the same thing.
However, in QuickBooks Online, you can have a sub-customer, but they want people to use their Projects feature if they need to do jobs.
This article will only cover sub-customers.

Recognizing a Sub-Customer in Method:CRM
The name of the sub-customer will be prepended by its parent customer, separated by a colon.

In the above diagram, Bob Crenshaw is a normal customer. Below Bob is Brigette Shawcren. Brigette is a sub-customer of Bob Crenshaw.
If you take a look below the bolded name Brigette Shawcren, you see written Crenshaw Construction:Bridgette Shawcren.
The colon indicates that Brigette is a sub-customer of Crenshaw Construction.

How to Create a Sub-Customer in Method:CRM
To create a sub-customer, the customer will have to exist.
Furthermore, you cannot create a sub-customer for a lead. Attempting to do so will convert the lead into a customer.
1. Select ⊕ New in the Contacts App or click ⊕ New Contact from your Contacts List.
2. This opens a New Contact screen. Make sure the Customer option is selected under type of contact you wish to add.

3. Under Job/Sub-customer of, select the main customer this new sub-customer is under.

Once you save, this person will be a sub-customer of the customer you chose in Job / Sub-customer of.

Differences between Method:CRM and QuickBooks
Out-of-the-box, Method:CRM treats sub-customers as a completely separate entity from its parent. Because of this, there will be these differences between Method:CRM and how QuickBooks handles sub-customers.
When creating a new sub-customer, the address from the parent will not auto-fill.
The balance of the sub-customer is separate from the balance of the parent. Thus, you cannot bill with parent in Method:CRM. Furthermore, the balance for the sub-customer will not be added to the parent of the sub-customer.
In QuickBooks, sub-customers are indented beneath their parent. In Method:CRM, a sub-customer is listed separately.