I believe there is a way of using a "subdermal map" with the Subsurface parameter of the aiStandardSurface shader so you can target what areas of a mesh show more of the chosen subsurface colour, e.g to target ears on a mesh of a human head with SSS so they appear more red on the inside. If you just use the skin shader preset as is, the ears look light pink, like a plastic doll.
Is the subdermal map meant to be a greyscale texture? And where exactly do you plug it in -- Radius?
I am assuming you would manually paint on the map in a program like Substance Painter and export it to Maya. Any one have any experience with this, or a tutorial?