# boundary condition in COMSOL

I deal with PDE module in COMSOL and I would like to simulate Poisson's equation. Actually I need to simulate the distribution of the electric filed created by the spherical probe in the material, hence I need to consider at least two different domains: air and material. Air and material have different properties, so that I need to create a two seperate PDE modules for air and material respectively. I faced with a problem that I don't know how to specify continuity condition on the boundary between the air and material. Comsol allows me to specify only one boundary condition, however I need to specify two:$$\phi_{air}=\phi_{mat}$$ $$\epsilon_1\frac{\partial \phi_{air}}{\partial z}=\epsilon_2\frac{\partial \phi_{mat}}{\partial z}$$I know how to specify one condition but not two. Could anyone suggest me how I can specify both those conditions on the boundary in COMSOL?