Force DPM boundary conditions on a sliding interface zone?
 

I am modeling a reactor with a vibrating deck that has fluid flowing through it into the main body of the reactor, meaning that there is a sliding interface between the (porous) vibrating deck and the reactor interior (see attached). All I want to do is make sure that fluid can flow through this interface while discrete particles cannot. Unfortunately, there is no "DPM boundary condition" dialog option for the interior portion of a sliding interface. The only way I've been able to do this is to change the "interior" BC to a "porous jump" BC, which does have an option for DPM boundary conditions. Unfortunately, this porous jump is creating a lot of convergence issues (I had to change my time step from ~0.001 seconds to 1e-7 seconds so the computation time is outrageous) and the porous jump model is not compatible with the main multiphase model I will be using from now on (Eulerian multiphase) so this is not a long term solution.

Is there some way for me to, say, upload a UDF imposing this DPM reflect boundary condition on that interior interface zone? Since there is no option to impose a DPM boundary condition on interface interior zones at all, it's not as simple as hooking a UDF to one of the dialogs in the guided user interface of Fluent.