How would I write the macro script so that one must hold down more than one key to activate a verb?
You can't with any sort of accuracy.
In response to Garthor
Well, I'm making a game that has diagonal shooting, and I was hoping that by holding down, for example, the north and east firing keys, that the player would start firing northeast until releasing either the north or east firing key. According to the DM Reference... "Macros are just like aliases, except that they are triggered by a single key (or combination of keys) instead of a full command.". So you're saying I actually can't do this?