For assemby outlines how to draw it seperately?

Hi.. I had finished my four layer board with allegro PCB editor. In that i had drawn the board outline with the outline option. In case, i want to draw outlines for bottom, signal, ground, top layers with SST, SSB, AST, ASB, SMT,SMB layers too.For fabrication the layers with outlines will been get provided for DFM. So i want to draw outline manually or any option is there for this option. Thanks & Regards Dhamodharan