Automatic Word Replacements

[Glock]

I asked this over on vbulletin.com and was told that preg_replace on post input might be the way, but was told to ask over here about it. I have no clue what that is in the first place, or how to do it. Basically we were served with a court order where we must removed both initial acronyms and multiple word ones, such as ABC and Adam Boy Charles. Basically, I'm looking for a solution that automatically changes these terms to something else, like Banned Term. The problem with replacements on vbulletin is that if I do an automatic change with both Adam Boy Charles and Boy Charles, it ends up looking like Adam BANNED TERM, which obviously doesn't work. Anyone have some solutions to this?