Press a button on arduino to open a file?

Its working perfectly! hopefully this will be my final question for you guys. I want to set up 2 keyed switches at opposite ends of the room so there must be at least 2 people there to activate the highest party mode. how do i set up a timer so when it senses that both inputs go high within 1 second it activates the final level?
Thanks very much for your help you have been very informative.
Demir