About how to get forces between two atoms groups

Dear lammps users,

I am running simulation between nanotubes. each nanotubes are given a group name. Now I want to calculate the force between any of two nanotubes. I tried to use compute goup/group command but my pair potential is Airebo and this potential is restricted in compute group/group. Is there any other possible way I can calculate force between two atom group using manybody/3body potential.