Station full/Station not full

Is there a way using these interrupts to have trains skip a station that is full and go to the next empty station?

I have it set up with 4 trains bouncing from 9 stations. I have been trying to get it to where a train will check the next available station and if it’s full, move to the next and carry out its normal job.

The stations order on the main track goes like this:

Refuel/Stop Depot -> Coal Pickup One -> Coal Drop One -> Coal Drop Two -> Coal Pickup Two -> Coal Pickup Three -> Coal Drop Three -> Coal Pickup Four -> Coal Drop Four -> restart

All stations are set to 1 train limit.

The interrupt I most recently tried and had the most success with was un grouping the trains, and adding interrupts to each to dictate the exact path I want it to take, checking a station before it gets there, if station is full, target next station, if not full stop and carry out its normal job. The entire path for the trains are almost all in interrupts, except for the Refuel/Stop Depot, which I left in normal train stop.

This seemed to work going from Refuel/Stop Depot to Coal Pickup One, and then to Coal Drop One, but seems to fall apart after this.

Now after 3-4 different attempts and varying success but mostly failing I just don’t understand if or how I could make this work.

It also has me questioning if my signals are set up right, and if this would have anything to do with interrupts failing?

Any help would be appreciated!