1 nozzle, 2 extruder setting

I have a FT-5 with a Prometheus V2 setup. Basically a “Y” into one hotend with 2 extruders. Astroprint sees it as two nozzles and has a second nozzle temp. Then you try and use the extruder part of the astrobox, it gets en error because the extruder 2 has zero temp. Please help!