How to set an "hard" ragdoll

I know unity not support softbodyes so I have an idea, (and it works on cinema 4D physic engine)if i rig the object, and i set it to ragdoll i think i can achieve a good physic effect. (yes i know physic of unity run on only one core, and lot of bones: lots of lag, but BeamNG drive uses this same system and i think this is more good than using a cloth mesh. The question is how i can make a ragdoll that moves only if a certain force is applied.