Need to have a Delivery split based on number of line items

What are best possible ways to have a control on the delivery creation based on the no. of line items.

Scenario : Suppose if i have a sales order with say 1200 lines (same to ship to party, same del date & Same Shipping point) and suppose if i want to have a deliveries created for this order that should not exceed 400 lines (hence 3 deliveries for the same order), how can i proceed?. Kindly Advice.

Thanks & Regards

Ilango