If an Action bases its effects around Invaders with a specific amount of Health (e.g., 3 Health worth of Invaders), what does it mean for that Action to affect +1 piece (e.g., for the Intensify Aspect)?

If an Action bases its effects around Invaders with a specific amount of Health (e.g., 3 Health worth of Invaders), what does it mean for that Action to affect +1 piece (e.g., for the Intensify Aspect)?

Also affect any one piece that meets the original requirement. In the 3 Health worth of Invaders case, this means any one Invader with 3 Health or less.