Is combining WebXR and AR.js possible?

I have been trying to use ar.js to find a marker and then anchor the object in the real world using webxr (immersive-ar).
I am able to get raw camera access and then pass it to ar.js to find the marker. And it is able to successfully find it.
I have setup two scenes since the projectionMatrix of both AR.js (arController) and WebXR (view.projectionMatrix) is locked.
Now the problem is I have to mimic the AR.js markerObject in the WebXR scene.
The closest I can reach is the following code:

function newRelativePositionMatrix(objectA, objectB, objectC, objectD) {
    // Get the matrix of object A
    var matrixA = new THREE.Matrix4();

    // Get the matrix of object B
    var matrixB = new THREE.Matrix4();

    // Get the matrix of object C
    var matrixC = new THREE.Matrix4();

    // Get the matrix of object D
    var matrixD = new THREE.Matrix4();

    // Calculate the relative position of object B to object A using their matrices
    var relativePositionB = new THREE.Vector3();
    relativePositionB.sub(new THREE.Vector3().setFromMatrixPosition(matrixA));

    // Calculate the relative position of object D to object C using their matrices
    var relativePositionD = new THREE.Vector3();
    relativePositionD.sub(new THREE.Vector3().setFromMatrixPosition(matrixC));

    var inverseMatrixC = new THREE.Matrix4();

    // Set the position of object D to the calculated relative position

How do I go about this ?
Am I missing some fundamental piece ? like the relative scale of a AR.js scene vs the WebXR scene, etc

Hi, sorry I don’t have and a answer but could you share please how do you get access to the raw camera on immersive-ar?

I don’t remember exactly. The data is not directly available but the workaround was to get it through the webxr api. And when I mean raw access, it means I had the camera feed as pixel data.