Anchor points and motion in Fresco

Hello all.

I'm trying to put some motion on my drawings. Im used to working with After Effects.

Is there no concept on an anchor  or origin point for a layer? I want to rotate a layer using motion but I dont want to rotate it around the center of the layer. I want to be able to rotate it from a point of my choosing. (the anchor or origin point)

My example is an arm on a character. I want to rotate around the shoulder and not the elbow.

Hope this makes sense.