how to set box2d fixture filter property for CCArmature's bones?

hi,
i’m new to CCArmature, i checked the process of constructing a CCArmature from a CocosStudio-exported .json file, I noticed the contourdata in the .json file will eventually become a box2d body so the collision detection is enabled…

But i don’t see a very straight-forward way to setup collision groups for CCArmature, cos for each box2d body of a bone, the fitler propery of its fixture will be the default value, then the only way for me to redefine the filters would be traversing the bones of the CCArmature, and go through each bone’s b2body list, and set the property of each b2body.

I’m just wondering is there a better way to set the fixture filters?

Thanks