Interesting (algorithm) problem needs solving...

[shamshasan]

I had an interesting (impossible) problem that I was working on that I figure you guys could help me out with:

• I have a universal set of printers: O1, O2, O3,... Ox, Oy, Oz
  • list maintained on Server-A.
    

  [*] Subset [O1: O3] will be made available to all other MACHINES via script.

  [*] Anyone USER can add subset [Ox: Oz]

  [*] For example: User-S has: [O1, O2, O3] & [Ox]

  [*] User-S also has similar object not on OUR list (Server-A) Uu, for example a USB printer, so:

  • User-S: [O1, O2, O3] & [Ox] & [uu]
    

Now... if I destroy O3 from Server-A. I want to be able to destroy O3 from all machines too; without destroying [Ox] & [uu] off of the user's profile.

But I don't have any memory on the user's profile and no memory on the server. So how do I do a comparison of sorts to figure out:

- remove O3

- don't remove Ox, Uu

Know any algorithm that would do/take-care-of this?