Man pages matching name mpi_win_get_group in section 3:

MPI_Win_get_group.3.en	debian 10 / lam4-dev
MPI_Win_get_group.3.en	debian 10 / mpich-doc
MPI_Win_get_group.3.en	debian 11 / lam4-dev
MPI_Win_get_group.3.en	debian 12 / lam4-dev
MPI_Win_get_group.3.en	debian 12 / mpich-doc