You want to use the 1905 functionality "Mark Several Items for Deletion in Goods and Services Receipts".
SAP Business By Design
New functionality introduced with 1905 release.
Go to the Goods and Service Receipts Work Center.
Go to the Purchase Orders to Be Delivered view.
Select Outstanding Purchase Orders and find a Purchase Order with more than one item to delivery.
Click " New Goods and Service Receipt".
Under items you are now able with press the Shift button to mark all items and click remove.
SAP Help Portal: What's New in Supplier Relationship Management
New Goods and Service Receipt , KBA , AP-GSP-GSA , Goods and Service Acknowledgement , AP-GSP , Goods and Service Acknowledgement , How To