Ability to use a mask paint layer from Substance painter to edit a Substance designer material

I would like the ability to draw inside a mask layer and use that as a bitmap within the node graph. So the painted mask can impact the designer graph. For example I have created a vein material that uses a single mask and goes through a scatter node to add small branching veins. I would like the ability to paint the original vein mask in substance painter on an object and have that automatically get the branching veins and fit within the material made within the graph.