Merging Deliveries

We have a scenario at several of our sites with customers either ordering stock orders or updates to prior orders and they want the deliveries merged. We have been given a manual process to delink line items from assigned delivery numbers and then relinking them to a new "unified" delivery number. This is a cumbersom process and leaves a risk for lines to not get reattached / linked to a delivery number. Is there a tool or product that can simply be provided with a list of delivery numbers to merge and do all the work automatically?