How do I hook up a seperate Xfinity account for an ADU on the other side of our property?

We already have Xfinity internet here.

I am adding an ADU with an apartment towards the back of my property. I still have the trenches open from running my power and water to the ADU.

The Xfinity service box that comes onto our property is right where the new electrical lines start.

Is it possible to branch our service and run another setup to our ADU, so that our renters can have their own ISP? Is it as simple as me laying some fiber optic cable? Or will Xfinity send a tech to run the line and set it up?

I already have ditches opened up, just trying to figure out how to proceed.

I've been on the phone with Xfinity for about two hours, I finally got through the robot phone tree and so far I've been passed around to three separate foreign teenagers. None of them seem to understand what I am trying to accomplish here.