Please Help~

I can't find the answer to my problem.

I run a project-finance department with multiple admin. staff supporting
different projects. I have a salary roster that I want to protect and hide.
However, my staff keep project budgets that required a certain amount of
salary info. to calculate our project labor costs.

I don't want any of my admin. staff to have access to or be able to view the
salary roster, only want their budget templates/ workbooks that I've built to
link to the hidden/ protected source file. I've tried to create my formulas
so as to keep individual salary data as protected and hidden as possible. My
understanding is that the source file MUST be open for the links in the
destination file to function.

Is there a way to create a hidden/ protected source file on a shared server,
so that the file can always be accessed by the destination files, without my
staff having to open and access the source file themselves??