You would need to have separate customer accounts setup for each delivery point - they are indeed a unique customer.  If the invoicing were then needed to funnel to a single entity but be separated by the delivery point, you would use the invoicing customer field on each customer to tie back to the main customer account.

Sounds as core function of ‘Create Collective Customer Invoices’? As long as you get customer order identified with different document address, they will be grouped in one invoice.

You could also use Collective Customer Invoices per order to select what orders to be invoiced in one, more flexible but human interfere needed.

Thanks, that's a good idea! I will put that to the finance team and see how they feel. 

Was hoping it was a simple setting in IFS I had overlooked