You can merge the attachments of the T+E Items and create a merged PDF on the T+E Report level.
In the T+E Report, click on the "Merge Attachments" link.
After clicking on the link a window opens and will display the result. This might take 10-30 seconds depending on the number and size of the attachments.
If it times out, check the Google Docs, Notes & Attachments section of the report.
The PDF is PDF/A-1b compliant and has bookmarks with for the individual T+E Items for easy reference.