A situation came up in our game last night where a hero was adjacent to TWO shadow dragons (Master and Regular) when attempting to make an attack. (Grizban was making a whirlwind attack, but I'm not sure that is relevant.) The ability affects the hero no matter which monster he is targetting, as I've read in other posts.
The question is: does the hero need to roll TWO surges for the attack not to be considered a miss? In other words, does the Shadow Ability Stack?