You will have to wait until the Mlods are released.
As of now there is only sniper and some civs with a hidden selection and that is the whole bosy, for you too create one from them would take alot of work and to create one from the ones that dont have hidden selections well its 8 times more work.
what those people are saying is correct but for now you can test by using the wodland guy or siniper , put one in editor and mess with the hit command or newer ones, use the command
this setobjecttexture [0,""] , his whole body will disapear . what you want is to use the Hide animation but again you will need Mlods .
Look up Hit_head,Hit_body,Hit_hands,Hit_Legs on the Bis Biki , these are the things that will help you determine where the unit was hit and what Gib to create.
Not sure but you maybe able to use selectionposition to place particle effects etc more presice too.
In additon they have rvmats and wound rvmats that will need to be negated for your mod.
good luck i will comeback when mlods are out.
Good luck