"Hidden" accounts

[Voratus]

Does anyone have an idea if it would be possible, and if so how easy, to make user accounts "hidden", in that browsing the users they wouldn't display.
I can only imagine creating a new field in the accounts table called "hidden" (for example), and making it either 1 or 0, 0 being default.
Then in the list.php, adding in to not display users with a ['hidden']==1.
The syntax of the list.php isn't as simple (to me, at least) as other pages, so I don't really know of a way to implement it there.
The reason is I created an account and took away its display name, and I use it to denote simple actions, or to RP the NPCs. However, it still is listed on the warrior list, just with no name (and level 0). I'd like for it to be invisible.
Or, a way for an admin to enter complete text in a "chat" page, instead of "charactername says" or "charactername does".

(edited as I changed the internal wording around)