If you just want to delete them, whenever you're on your home page, just go to the far right where it says your network and whatever, and at the bottom under that, it should say "My Groups", and just click on that and all your groups'll show up. Then just go to each one of them and if you want to leave them, go look at their picture and look at the blue buttons, and the top one or second top one should say "Resign", and just click it and you should leave the group.
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