welcome wokmichel!
there may be several solutions to your problem, and i don't know the best one since i don't know your situation in detail.
anyway, if kremlin's advice doesn't fit your needs, you may try creating a fake account, with impossible password, and restrict to that account the stuff you don't know yet to who you will give access.
also consider using user groups, available in version 2.3 (currently in beta, but very stable)