It doesn't currently support multiple IR receivers.
The easiest thing would be to AND the receiver outputs together (since the sensors are active-low) and provide this as a single input to the Arduino. This would work if only one receiver is being used at a time, or if they are receiving the same signal. You could also use multiple Arduino inputs and do this AND logic in the interrupt routine, testing if any of the inputs are low.
It would be fairly difficult to support multiple IR receivers that could receive different signals simultaneously, as each one would need to be tracked independently.