We have added this ability to our MOSAIC Utility command line tool version 2.2.6 - Mosaic Utility Driver (nvidia.com) for support of our Ampere Generation of GPUs i.e. NVIDIA RTX A4000, RTX A5000, RTX A6000 etc.
For a 2x2 array like the following:
the command line will be
configureMosaic.exe set rows=2 cols=2 mirroring out=0,0,vhm out=0,1,vhm out=0,2,nm out=0,3,nm
mirroring - enables the mirror options
vhm - vertical & horizontal mirror
out =GPU,Port,mirror - top left display is 0,0,vhm