Hi Niky,
as we are dealing with real 3D spaces within Pandoras Box you will not find a "Mix"-option. The catalyst feature is a two-dimensional compilation of layers which are just rendered onto each. In there you can select layers to be visible or not.
In our world, you need to setup your cameras in order to define your visible areas from the 3D space. Within the next version, you will be able to select layers to be visible for all cameras, or only for selected ones. As you want to have
more areas within
one camera you need to use some workarounds.
You can use the blend modes for defining areas in which layers become visible.
The composition-effect "render history" would be another way to define more layers to become visible on a single layer. This one can then be scaled, moved and defined into the specific area. All layers behind a z-depth of the layer using the effect will be routed to this one.
Have a look here:
http://www.coolux.de/root/downloads/sup ... siting.htmPlease do not forget to toggle the first topic for detailed information.
Hope this helps!
Markus