Question About Multiple Screen Mosaics

My OS is Ubuntu_x64_18.04, graphics card is gforce RTX 2080, graphics card has multiple output ports, each output port connects a screen, a total of four screens.We use the system settings or the nvidia xserver settings to complete screen stitching, the four screens can be stitched together, that is, the main screen is on the left side, the mouse moves to the right, and in turn can be moved to the second screen, the third screen and the fourth screen.
However, this splicing belongs to the way of expansion, that is, the status bar of the main screen is displayed on the main screen, and will not extend to the right side of the expansion screen. If we maximize an application (such as file manager, text editor, firefox), it will only maximize on a single screen,but not the overall maximization across the main screen to the fourth screen.
Because of the specific application requirements, we hope to put these four screens together into a single screen. That is, the status bar can span the entire four screens, and the maximum window should span four screens. Can this be set from the system or nvidia-settings software?
There is no twinView in version 18.04. So How can we realize the setting of splicing into a single screen?
Thank you very much!