Physics list per volume

Hello,

I need single scattering and precise EM physics for a single volume (EMZ for a crystal). However, in my model I also have metre long blocks of copper where regular multiple scattering and less precise EM physics is more than sufficient. Just now I have one physics list and despite using regions with different range cuts is just much much slower.

Is there a way I can have msc in certain volumes / regions but not in others?

Thanks,
Laurie