Modeling piezoelectric with a non-piezoelectric material

Good morning.

I'm trying to model the mechanical behavior of a piezoelectric material on top of a non-piezoelectric material. Because the bottom material is non-piezoelectric, COMSOL does now allow me to use the piezoelectric modeling because the necessary constants that COMSOL needs for a piezoelectric study are not present in the non-piezoelectric material (this makes sense).

How can I model this structure? I know COMSOL is suppose to use multi-physics for something like this, but I do not know how to let it know that one material is piezoelectric, and the other material isn't. That way, it only applies the piezoelectric constants and equations to the piezoelectric material, and then calculates the stresses and strains for both the piezoelectric and non piezoelectric composite.

Thanks for any help