This is rule #1.
Only one copy of any document should be submitted (per project).
If you find yourself sending in the same information more than one time, there is a mistake being made. If a document relates to various items, you should be adding/updating metadata to the document, to identify all possible connections. The Customer data system should be designed to cross reference one document to multiple pieces equipment – at least within one project.
Look out for rule #2 later this week!