[phenixbb] refinement in low resolution

Hi I am trying to refine the model in low resolution and there are multimer in the asu. I did rigid body refinement after MR , molecule did not move much and R/Rfree stays 45 % and If I do the overlap between the monomers, rms is 0.06. If I do simulated annealing or any type of refinement (group_adp), Rfree is high and R goes down, but the if do the superposition of the monomer, rms is 1.5 to 1.8. So like to know what kind of refinement is can be done in very low resolution between 5 to 6 ang data? Is it any strict ncs could be possible in phenix that should not move the monomer too much? suggestions are appreciated rn