More about Check ChildStates while typing

I see that I can define a KeyPressTrigger that may work for my special purpose of detecting keys pressed, however the triggers seem to be only Character based. Can we define a regular expression for the trigger like
[A-Z]
so I can trap for all key presses while in my <KeyPressTriggerValidState State="CommentState"> or do I have to setup a KeyPressTrigger Character for every character A-Z ?

The reason I need to do this is I activate the intellprompt feature for any letter A-Z typed to show the user all commands available as they type. However when in a CommentState I want to disable this so I can type comments that do not relate to commands.

Thanks
Ernesto