Data Validation from other Workbook using SharePoint URL?

[neim0003]

Hello! I am trying to list of values from 1 workbook (Source.xls) to be the dropdown list in another workbook (Destination.xls). I see how i can do it when book workbooks are open in the instructions here, but i'd like to see it can be done without the workbook open using a URL. Both documents will be stored in SharePoint.

Goal:
1. Have user enter the URL of Source.xls into a cell in Destination.xls
2. Have user be able to write a formula in the DataValidation to read the URL from #1 to create the dropdown values.
3. Assign the validation in #2 to another cell in Destination.xls

Is this possible?

[neim0003]

Is this not possible? Is that why no one has advice?