Patterned ground shield in HFSS

I want to simulate an inductor with a patterned ground shield (PGS) in HFSS. Physically, the PGS consists of lots of traces in the lowest metal layer. When I draw all these traces (even as 2D surfaces), the mesh is too large and the simulation dies with an out of memory error. How can I simulate this structure without adding physical memory to the computer? (Plus, I want to reserve the memory for a high density mesh in the inductor coil to accurately calculate Q!)

I've thought about defining an anisotropic material, with high conductivity in either the X (or Y) direction, and zero conductivity in the Y (or X) as well as Z direction. And then put a thin layer of this material in place of the traces, with the high conductivity direction always parallel to the trace direction. Would this setup give accurate results?

And does HFSS let you define anisotropic 2D boundaries?