Triggering timed events?

Greetings, a simple question realy..and after searching the forums and finding different aspects, I'm trying to figure out how to time two events together.

Basicly, I need Attachment A(Person 1-wearing) to be able to have a set timed listen, say once every 30 mins. and only then listens for example, 2 mins. where another person/avatar(Person 2) can say a trigger command, and start another timed event within attachment A that cancels out the original listen and then runs other events.

I've got the basics for the other parts, but I can't seem to figure out how to set this particular part up...any ideas?

the first thing that comes to mind is using states

in default just set a timer for 30 min (1800 seconds) when that event happens jump to another state that resets the timer to 2 min and opens the listen, when that timer event happens reset the timer again, kill the listen and jump back to default

(note timers continue to run tween state changes, thats why you have to reset them)