One EA signals on two different charts?

I was wondering if it was possible to trigger an entry based on an hourly chart moving average, and have the exit based on a 15 minute chart or 30 minute chart moving average.

Is this possible within ONE EA, or would two ea's and two charts be needed one for the entry and one for the exit.

EAs can call data from different timeframes.

Yes. When calling an indicator, change the Period to whatever chart you wish.
Also, if using CloseOpen, use iClose() and iOpen() instead, to account for different timeframes.