Secret Message VBCode?

[Zowners]

Hey everyone, this is the admin over at OfDiceAndMen.com (a role-playing forum) and I've been racking my brain over a problem and I was wondering if you guys could lend me a hand.

Basicly I'm trying to build a new VBCode that would allow my players secret messaging abilities without clogging up their pm boxes. I would call it the "GM" tag (stands for Game Master in case you needed to know). At first I thought this would be an easy edit of the already existing Spoiler tag.... was I wrong..

So the code is HTML/VBulletin from what I can differ, but know my only knowledge on the subject has been trial and error and a few "HTML for Dummies" websites. I mean adding my first bannar to the page was huge accomplishment to me.

So what I need:
For a person to type as if any other VBcode, one with a conditional just like the spoiler's title, in this case a username:
ex. {gm=Inquisitor}You smell{/gm}
Now that message, upon hitting submit will get scrambled and encrypted, the effect I want is that ONLY the person who's name is in the tag, in this case myself, to be able to read the message. Beyond that I don't care the other stuff in case someone else veiws it, blank, black lines, garbled gibberish, whatever. Another method I've thought about is that the message is hidden like a spoiler tag, but only a member whose name is in the tag can hit the "Show" button and get a result.

Other little features that would help is if the original poster can edit the post without messing up the message or even better be able to alter the message once it is sent (I understand this one is tricky), and also that Administrators have the ability to "crack" the code so that no bad stuff is going on.

So tell me is this possible or should I just increase everyone's PM space?