genocide once more

I had a post earlier on the philosophical relevance of the concept of genocide a while back. But it occurred to me that the main reason why I gather genocide is so bad is because it is not only a crime against each individual in a victimized population but it is a crime against the group as such. Thus it would seem to be worse than mere democides or mass murder on a comparable scale because these other kinds of mass killings etc may be seen as nothing over and above the crimes perpetrated against each member of the group added together. Because there is the further crime against a group as well as each individual within it, genocide is a crime over and above the other kinds of -cides. Perhaps this shows that most people's intuitions on the badness of genocide shows that (or at least compels them to admit so) a group of people (which is a collection of individuals and hence an abstract object unlike a person which presumably is a concrete object) as such has certain rights. But what kind of rights do groups have other than those protecting them from genocide and how are they related to individuals' rights within groups?