You sure can! On the Settings > Functions tab, assign a key combination to the "Mirror Monitor" function. When you press the key combo, it will prompt you to select a monitor. After you choose one, it will show it's output in a window on your current monitor.

You can use the Splits and Padding button in the DisplayFusion Monitor Configuration window to split the monitor into 4, or you can just use the "Move Window to Top-Left/Right Corner and Size 50%" and "Move Window to Bottom-Left/Right Corner and Size 50%" functions to size them without using the Splits and Padding.

Hope that helps! Please let me know if you have any follow-up questions