Hi Einstein, yes a third part like jiglib,box2d or wow will ease the work: the one you'll choose will depend on the kind of interaction: if jiglib and wow will really acts as 3D physic engine, box2D can be a good choice if your interactions are done on a same level (like on a floor for example), as it's only a 2D physic engine.
Google it (if I found time I'll send you some links).
