Four 4K external monitors connected to XPS 17 9710

HI,

I have connected three 4K monitors on the USB-C ports, it works fine.  Also  with the notebook display I have four 4K monitors .

Question: Waht I need to connect  a fourth 4K Monitor ?  Also togehter five 4K monitor included the notebook's monitor.

If it not possibe, than it coud be a 2K resolution as well.

Thanks in advance,

Michel