Calculation of coordination number on a surface

Hello dear users lammps!

I want to calculate the coordination number (CN) CN Ni-Ni, Ni-Al, Al-Al, Ni and Al, on a surface of nickel, in which I am depositing aluminum. My system would not homogeneous because I will have a single region of Ni and a Ni-Al mixture. My interest is on the region of mixing.

I appreciate your attention and any information I can offer …
regards