Premium Mosaic custom resolution

Hello, guys!
I have 3xQuadro K5000 and Quadro Sync in my setup.
I need to make 6192x3060 desktop via Premium Mosaic. 3x4 monitors with 1548x1020@60
How can I make custom resolution for single display(1548x1020@60) or whole desktop(6192x3060@60)?
Is it possible?

7680x3240 - no problem. But I need 6192x3060…

Can anybody help me?