I'm guessing you're working with a pdftex-based latex system. (The two other main TeX engines, luatex and xelatex, use a completely different system of accessing fonts on the system.) I further take it from your description that various types of grants are associated with various types of font access rights, i.e., not every grant holder is allowed to use all of the fonts on the system. In addition, I also assume you're on some kind of unix-based operating system.
If your system is indeed unix-based, why don't you just define various "groups" with different read-access rights to various fonts, and then assign your grant holders into various groups depending on the font access rights they're supposed to have. Put differently, let the operating system do the heavy-duty work of maintaining and supervising access to the fonts.
Finally, if the fonts in question aren't distributed by default with whatever TeX distribution you have but are purchased separately, it would be a good idea to store the fonts somewhere in the LOCALTEXMF directory tree rather than in the main TeX distribution. That way, updates to the main TeX distribution won't affect the fonts, and vice versa. Happy TeXing!