Making things specific!!!!!

Recently I have heard from someone who has done a lot of research into Tweenagers, that age range from 10-13. they have looked at resources and idfferent issues around this age group. One of the interesting things that seems to have come up, is the difference between the younger end of the age-range and the older end. Is it possible to make something specific for the olders ones, and something specific for the younger ones. At the heart of the question, is making things specific, rather than just goruping people together. God doesn't group us all together, he looks at us as individuals, and treats us as individuals, so why don't we look at people as individuals? So let's remember that everyone is different, and has different neds and outlooks on life, and remember that God treats us as individuals, so we should do the same to others.