Welcome and thanks for visiting our forums. I can share some insights on how to set up multiple child support withholdings in QuickBooks Online.
At the moment, QuickBooks lets you add up to two active garnishments per employee at a time. The system will let you choose the order to be deducted to their disposable income. In your case, since you need to add more than two child support items for an employee, I'd recommend contacting our QuickBooks Online Care Support.
They have the resources necessary to update your employee's additional garnishment order. To contact us, follow the steps below:
On your QBO Dashboard, click the (?) Help menu.
At the bottom, click Contact us.
That should get you pointed to the right direction, @Anonymous. To know more about handling wage garnishments, please checkout this article: Set up and assign garnishments
Please update me on how it goes. You got me here if you need further assistance with QuickBooks Online Payroll. Wishing you a great and productive day!