I don't remember if the rules have changed on this:I had enchanted AI's War Mammoth with Mire Blight in combat AI blocked with it a creature that could kill it also with normal combat damage,so it suffered lethal damage from combat damage but also the destroy effect from being dealt damage from Mire Blight effect.AI regenerated the War Mammoth with an Elephant Graveyard.Can this be done with one source of regeneration while it suffered 2 different causes of lethal damage.For the record AI had a 2nd Elephant Graveyard which wasn't used.