Model Heat transfer through a wall

Hello,

I'm having some difficulties in setting up a heat transfer model which involves heat transfer through a wall.

I've attached an image of my setup and what I'm trying to do.

I want to model heat transfer from a heat source (meshed wall A) through a powder (Powder B), through Wall B and onto Powder B.
As you can see from the attached image I cannot set up the model to allow heat to transfer through Wall B (which is an imported mesh).

I'm hoping for some guidance on how best to go about achieving heat transfer from Powder A to Powder B whilst keeping the two powders separate. Is it possible to achieve this using existing LIGGGHTS commands or is this a case of using a DEM-FEM coupled approach for this?

Thanks in advance.
Jon