Which sensors are we talking about? Most IR logic sensors like the TSOP1838 have open-drain outputs so they can all be connected together and directly to a digital input on the Arduino.
Now, of course, if two sensors are both being hit by infrared light at the same time you will probably get garbage, but as long as only one sensor is receiving IR light at a time there's a good chance it'll work.
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The Gadget Shield: accelerometer, RGB LED, IR transmit/receive, speaker, microphone, light sensor, potentiometer, pushbuttons