Maya Animation :: Skin Conversion To Muscle System Without Converting Every Single Joint To Polygon Bone Object

Any way to do the skin conversion to muscle system WITHOUT converting every single joint to a polygon bone object. I'd prefer to manually create the muscle bone objects from only the joints I plan to use for the muscle system, and then do the skin conversion using only those joints already converted. Basically, I only need a few muscles in this system and therefore only need a few polygon bone objects, but as far I can tell, there is only one way to do the skin conversion and it automatically converts every joint that the skin is attached to.