Export Multilayers within an Artboard? HELP

Hello, please take a look at the pic below

This is a file with multi Artboards in varies size, in each Artboard i have many layers.

What i want is to export every layers in the size of the Artboard that they're in

(ex: A,B is child of Artboard1 which has size 100x120, so A & B will be exported into 2 files has size 100x120

C,D is child of Artboard2 which has size 400x500, C & D .... has size 400x500)

Err how can i do this, please help me T.T i have like over 100 Layers and i need each group to have a identical size