How to use integrated Intel and dedicated nVidia graphics to power different monitors?

I would like to add another monitor and power it using Intel's integrated gpu as the nVidia card cannot power any more monitors.

I've confirmed that the cpu supports Intel's Flexible Display Interface (FDI) and that my bios is set up correctly (the later using the motherboard manufacturer's customer support and internet research).

I can even get all monitors to work using an Ubuntu live cd and the nouveau drivers. The issue with using nouveau is that it is highly unstable and tends to freeze my pc. Using nVidia drivers results in a stable setup.

When using nVidia's driver, the monitor connected to Intel's gpu lights up during boot up, but turns off when the login manager is displayed.

How to get both the nVidia and Intel gpus to work together with multiple monitors?

I am using Ubuntu 16.04.1.