say you have 5 sprites called red,blue,green,orange and yellow
you add all 5 to a family "boxes"
then to the family you add instance variables maxhealth and health
now each of the sprites have now also got instance variables maxhealth and health
so at start of layer you can say
but you can then say
when members of boxes hit
so if the area of damage hist a red, and green sprite then their and only their health will drop