Can't generate tpr file for calculating per residue free energy in g_mmpbsa

GROMACS version:2021.2
GROMACS modification: Yes/No
Here post your question : hello sir i did molecular dynamics simulation in desmond using opls-2005 forcefield.then I converted desmond trajctory file to .xtc & .gro file.But to calculate per residue free energy in g_mmpbsa (.tpr) file is my question is how to convert .xtc or .gro or .trr file to .tpr file ???
if I want to generate tpr file using original pdb file the problem occurs that there’s no opls-2005 forcefield in gromacs .