Hello Kim,
The standard application works just the way you describe.
A workaround is the use of naming conventions, as Rahul mentioned.
Alternatively, you can use findims for each customer to agglomerate and analyze the invoices at the parent level.
Using those naming conventions or findims does, however, not directly influence the way how payments are recorded.
How do you handle those?
Does it mean that a parent customer company pays the invoices for its children?
If so, do you get a payment advice from your customer what invoices have been paid or do you simply receive an amount of x$ that you then have to reconcile and settle?
Best regards,
Ludwig