A pastoral question on a beatitude

I'm leading a Bible study for teenagers tomorrow on the beatitudes - general intro, and then homing in on the first 2 (v.3-4). And I was wondering if someone can help me out pastorally.

In v.4, we have Jesus saying: "Blessed are those who mourn, for they will be comforted." In context, it appears as if this isn't just general grief for a sad or tragic event in one's life, but more specifically, a mourning over sin. (Very briefly, I take this line because the Sermon on the Mount is about kingdom living, and the way of the kingdom is the way of repentance. I haven't consulted any commentaries as I don't have one at hand, but I'm pretty sure the standard ones take this view and back it up). However, mourning over sin specifically doesn't necessarily preclude the former, since we grieve not only over our own sin, but sin in a fallen world, which affects every part of creation: hence the existence of natural evil, tragedies and so on. We mourn at the way sin twists and distorts our lives, both in the personal corruption of each of our own selves, and in the disruption of shalom, how things are not the way they ought to be. We find comfort in the gospel, that we are saved from the penalty of sin, and that one day sin will be completely gone.

I'm mindful that at least one girl in my group lost her dad in a tragic accident a few years back, and so such a verse will no doubt be a balm. I think at least another girl is from a single parent family, and who knows what lurks in the background of others in my group. So I want to be sensitive. But I do want them to see that Jesus is talking about mourning over sin in particular. So, any idea how to approach it? Useful phrases or remarks? Stuff that is simple but not simplistic? Any help much appreciated! I've got another 24 hours to think about it...