connecting jit.phys.body to jit.gl.gridshape in javascript

i want to generate many jit.gl.gridshape objects which are connected to jit.phys.body objects in javascript.
my code works fine, but since i set the gridshapes position and rotatexyz to the phys.bodies' position and rotatexyz in the bang-function (which is triggered by a qmetro 40), it uses a lot of cpu performance.
i also tried to do a similar patch using jit.phys.multiple and jit.gl.multiple (without javascript). but that's not an alternative for me, cause i want to change the x-, y- and x- scales of the objects on the fly.

can anyone explain how to connect jit.gl.gridshape- to jit.phys.body-objects using javascript only?

thanks for any help!

PS: below is my code which uses a lot of cpu-performance.

var maxo = 250;
var cside = 0.04;
var cube = new Array();
var cubx = new Array();
for(var i=0;i
{
    var r = (Math.random()*0.1)-0.05;

    cube[i] = new JitterObject("jit.phys.body","orjo-world");
    cube[i].shape = "cube";
    cube[i].scale = [cside, 0.1, cside];
    cube[i].position = [r, r, r];
    cube[i].friction = 0;
    cube[i].mass = 1;
    cube[i].restitution = 0;
    cube[i].damping = [0.99,1];

    cubx[i] = new JitterObject("jit.gl.gridshape","orjo");
    cubx[i].shape = "cube";
    cubx[i].shader = "orshade";
    cubx[i].lighting_enable = 1;
    cubx[i].antialias = 1;
    cubx[i].scale = [cside, 0.1, cside];
    cubx[i].position = cube[i].position;
}

function bang()
{
    for(var i=0;i
    {
        cubx[i].position = cube[i].position;
        cubx[i].rotatexyz = cube[i].rotatexyz;
    }
}

function resetit()
{
    for(var i=0;i
    {
        var r = Math.random()*0.1-0.05;
        cube[i].position = [r, r, r];
    }
}