Rendering Transparent Geometry Performance Issue

I'm developing a 2D game in which the characters have many different sprites for their body parts (one sprite for head, one for torso, one for shirt etc). On average, there are about 15 body part sprites per character. They have been designed in such a way that the size of the sprite is that of the entire body and the small portion of that body part that it belongs to (e.g. the head) is shown at its appropriate position. This means that each sprite has huge transparent areas, and this is leading to big performance issues when trying to render the characters (see image attached). I tried using the diffuse shader with a directional light but I'm getting similar performance. I read something about cutout shaders but I haven't found an example of a shader like this. Any ideas? Would using the 2D Toolkit help me solve this issue?