Mosaic +1 in RTX A4000

Hi all

Im building PC for video wall using 3x2 monitor
For 6 monitor i use 2 RTX A4000

I’ve configure mosaic for 6 monitor successfully, but i want 1 more monitor configured as non mosaic.

I’ve plugged 7 monitor in 2 RTX A4000, in non mosaic mode, all the monitors are active, but when i activated mosaic mode for 6 monitors, the 7th monitor was deactivated by system. What should i do.

I found setting named MOSAIC +1 but i can not implement it on my PC,

Thanks in advanced for your help.