My guess is no, you can't wire both of them to the float sensor. Basically, the float sensor is variable resistor (based on fuel level). Any device that is going to "read" that sensor would place a constant voltage across it and measure the change in current or run a constant current through it and measure the change in voltage. Either way, the two devices trying to read the sensor would interfere with one another.
You could do it with an in-cockpit switch that selected one or the other instrument. But you can't wire them both directly.
