[phenixbb] anisotropic refinement based on B values

I'm sure that this has probably already been covered but I am having some problem finding out how to tell phenix to make a decision whether to refine isotropically or anisotropically based on B factor values. Is this something you can do with a python script? Thanks. -Yarrow -- Yarrow Madrona Graduate Student Molecular Biology and Biochemistry Dept. University of California, Irvine Natural Sciences I, Rm 2403 Irvine, CA 92697