We would like to have the total energy and position of each atom
located in a specific region, during the simulation. To achieve this,
I think we can define a region and then assign the atoms of the region
to a group, e.g. G1. Then we can use total energies and positions of
the atoms of G1 for an specific computation. But I think the assigned
atoms to G1 are determined in the start of simulation, and they are
preserved; I mean the atoms of G1 do not change during the simulation.
I think the assigned of atoms to G1 should be updated in each time
step. Is it possible?