I think it is not straightforward to calculate these using GROMACS. Instead, you can use other tools, such as "freesasa", it wil give you total as well as each type of surface area. For this, you need pdb files that can be extracted and later using bash (or WSL), you can do it.

Just an example:

#!/bin/bash

set -e

for i in $(ls -1v ../S176P/packing/pdbs/*.pdb); do

freesasa --select "NLS, resi 87-95" $i -w -n 100 >> output.txt

done

Here, NLS used as title, and resi for residue index, like calculate accessible surface for 87-95 residues. You can use your own index.

Google it, and and you find its help as well. Pretty good tool.