Given the complexity of this I suspect the best way to achieve this would be to have something running on another server that had all the details of what went where and then populated it into the JSS in some way.
JAMF by it's very nature is intended to make things the same rather than different and given they are iPads I don't know what scripting options you would have here (which if it was macOS would mac it fairly straight forward.
You might also be able to address the issue somehow by having a remote source for the documents that was mounted / connected to the same way on all iPads, but then somehow identify the iPads at the remote end and restrict just to the ones intended for that iPad.
