Requirements to Create one Drop Ship Purchase Order from a Sales Order with multiple line items

After the Sales Order has been approved and saved the link appears on the line level called "Drop Ship Spec. Ord." which will generate a Purchase Order for the items. If the Sales Order has multiple line items one Purchase Order can be created for all items.

For this to occur the same Vendor needs to be selected as the Preferred Vendor on the Item Record.
To check this:
Go to the Item Record> Purchasing/Inventory tab> Vendors subtab
- Ensure there is a Vendor selected here and the Preferred column is checked

All of the items that have the same Preferred Vendor set on the Item record will be added to the same Purchase Order that is created from the Sales Order link on the item level.