Double Sorrow - When Joy turns to Sorrow

In Mathematics,

1 - 0 = 1, but
1 - (-1) = 2.

In prose, I have read, It is worse to have had (material goods) and lost than to never have had at all. That is why Americans are hurting so much more from this recession than (say) third world country denizens. Similarly, I was wondering if human's react the same to something non-material like joy and sorrow.

A family that was close to me (growing up), was about to have a double celebration. The two older sons were betrothed to two young women from a city 400 miles away. The extended family was sent ahead for the wedding on two large buses. The two grooms, their father, uncle and cousin were to join the rest of the group by car. Alas, they never made it. About half way through on the highway they were hit (almost head-on) by a truck. Three died on the scene, the other two a few days later in the ICU. What a tragedy!

I still weep sometimes when I think of that day but have always wondered if the tragedy would be less severe had it not occured in the presence of what would have been a joyous occasion. Is there something known as double sorrow?