exclude the interaction between the specific particles and wall

Hello Everyone!
I am working on the seepage-erosion problem, there is a cube with 0.01*0.01*0.01 simulation box with 6 mesh walls, and two group pariticles with different diameter, called fine and coarse, after consolidation with servo wall, I want to excude the top wall and the group fine particles, I tried to use three kind method which is discribed in documentation as followed:
"If you want there to be no interactions between a particular pair of atom types, you have 3 choices. You can assign the type pair to some sub-style and use the neigh_modify exclude type command. You can assign it to some sub-style and set the coefficients so that there is effectively no interaction. Or, for hybrid and hybrid/overlay simulations, you can use this form of the pair_coeff command in your input script:
pair_coeff 2 3 none"
but I found that none of the 3 method can be used to achieve my request, they are working to exclude the interaction between particles, but can not to exclude that between particles and mesh walls, so how should I do to achieve this?
Thanks!
Zhang