Drop Shadow recommendations for complex UV's

Let's keep it short and sweet:
I'm working on a pair of pants and I want to add drop shadows, but most details of the pants are separated on the UV (pockets, pocket flaps, differnet fabric, etc.) I'd like to add some shading around the borders of the different pieces of fabric to punctuate seams, but since the UV has most pieces of fabric separated, if I use a drop shadow or a fill layer with a color selection and blur, I get shading on random parts of the model. Anyone know any tricks?