Simulate a too large system

GROMACS version:
GROMACS modification: Yes/No

Hi everyone,
I have to study a system particularly large and I don’t have enough computational power. I want to study the effect of a mutation on a protein structure and its interaction with other proteins. We already have the results of in vitro experiments, but it is necessary to run some in silico studies to investigate the mechanisms involved.
To reduce the computational cost of the simulation, is it possible to simulate only a region close to the mutation site without considering the rest of the protein? Or considering the rest of the protein like frozen? Does such a solution make sense to reduce the simulation time?
Thank you