Forcefield to simulate RNA molecules containing modifications with GROMACS and amber ff

GROMACS version: version 2023

I am planning to do simulations of RNA molecules that contain modifications such as PSU, etc. I understand that for RNA simulations I should use amber14sb_OL21.ff package as the forcefield. And this package is gromacs compatible. However, in-addition, I also need to use this forcefield for modifcations. Is there a chance I can get this forcefield in gromacs compatible mode? Or any other suggestion is also welcome.