there's a comparably distributed memory option in HPC setup, which seems just like a simple domain decomposition mode, but task are sent to different machines in the cluster.. well, with domain decomposition you can solve even on single machine... but these decomposition modes are very, extremely slow, and do not use CPU multicore much.
HFSS Help > Specifying Solution Settings > Distributed Memory Solutions with HFSS > Setting up HFSS and Running Distributed Memory Solutions