Marlin Cooling Fan Select

I am finishing up my custom dual extruder mount and ran into an issue with the part cooling fans. The default extruder0 fan (FAN_PIN 8) turns on when cooling fans are turned on. I would like for the extruder1 fan (FAN1_PIN 6) to also be controlled by this setting. Is there a way to change this in the firmware? Or am I stuck just having to wire the two in parallel?