How to find the interaction energies between a solute and solvent around it?

GROMACS version: 2021.2
GROMACS modification: No

Dear GROMACS users,

I have a 10 ns simulation of a solution consisting of a solute and an organic solvent. Now I want to get the interaction energies (vdW and Coul.) between the solute and solvent molecules within the 0.5 nm of the solute.

I cannot define an index group for those solvent molecules, because they are diffusing in the solvent and we don’t have the same molecules within 0.5 nm of the solute all the time. So how can I get the interaction energies?

Kind regards,