Your screenshot is protected, so I cannot see it. I dont think there is anyway to change your screen identities without physically changing which ports they are plugged into on you GPU.

EDIT - I was trying to do this in Windows when infact DF can help.
Have a look at this post, it may be what you are looking for:

https://www.displayfusion.com/Discussions/View/modify-monitor-order/?ID=217abc53-aeee-4d34-a87e-b27c76583e46

"Does your solution require me to physically move my monitors around?"

No absolutely not! Just open the Screen Settings as described above and drag and drop the on display monitors to where you want them. They will all be assigned a number and that is the order that you will tab through you screens.

You can do this by right clicking on a screen and then on screen settings (I think its called that) then Your main screen should be No1, drag the other screens around so they are numbered the way you want the windows to snap/move.

For example my 3 screen setup is No3 - No1 - No2 and if I use the Winkey + arrows then it will scroll through the screens in that order (to the right).

An example of yours assuming you want the main screen on the bottom row and in the middle would be

No4 - No5 - No6
No3 - No1 - No2

It should now move through the screens to the right then up to the second or upper row but you can drag them around to suit your needs in any order and the scroll momentum will always be (or should always be) 1 to 6