In islam You can follow all the rules and come before allah, and he can still kick your ass out of heavan. Suicide bombing was a way to get everything you ever did wrong forgiven by killing innocent people to save your worthless ass. So it is the most selfish act out there.
Destroy their belief that they owe allah a sacrifice of human blood and they will turn.
My reccomendation is to tell them that the One True God, sent his Son to die for them so that God could love them without sacrifices.
Do you really think they will listen? I really think that they are under an evil spell or something, their beliefs are directly from SATAN (he's so happy with them)....I know, however, you are right my friend, we are required to do this, and hard, hard it is