There have been some big African suicide cults, info on the main site linked above and rumours of suicidal tendencies in Aum Shinrkyo, currently known as Aleph.
Basically, any cult can go that way if the leader is loopy enough to see death as a viable option to being unable to impose his will on the world and has enough control over the followers.
Interestingly, the dynamics seem to be similar to the men (it is mostly men though not exclusively) who feel powerless in the world for some reason and kill their entire families and sometimes, though not always, themselves as a form of revenge against the cruel world that will not submit to their will.
Corboy has previously linked to a good article on this:
I don't really get what you are asking for, do you have a particular group in mind?