Hyperlinks in an Excel file

I have many documents to be reviewed by several reviewers. Titles of the documents are listed in column A of an Excel spreadsheet uploaded to SkyDrive. These titles act as hyperlinks to the actual pdf documents which are assembled in a separate SkyDrive folder. In THEORY, a reviewer can be invited to share access to the spreadsheet by email, and without signing up to Skydrive can scan the list of titles and select a document to review by clicking on the title and have the document come up on their screen (and download it). In PRACTICE, this worked when I tested the process by sending an invitation to share the Excel file to my other email address, and responded from the same (Macbook Pro) computer I used to upload the Excel file and document folder. However, it did NOT work in a more realistic test when I sent the same sharing invitation to a colleague who does not have a SkyDrive account. She could access the Excel file in SkyDrive, but attempts to access the document by clicking on the hyperlinked title failed. I'd rather not have to 'share' all the documents with all the reviewers, and also not require them to sign up to SkyDrive. All suggestions welcome, thanks!