How to interconnect two Asterisk Servers with a SIP trunk Internationally

How to interconnect two Asterisk Servers with a SIP trunk Internationally
Is it possible to setup an asterisk box in ex. Colombia S.A and another in the USA, setting up trunks between the boxes to speak to each other via sip or aix, create extensions, forward any incoming call on that local extension to the other country Asterisk box and then forward that extension incoming phone call to a cell phone in Colombia and do the same if a person wants to call me in the states? I was hoping that this would be a very cost effective way for my friends and I to save a bit of money. Essential I want to internationally connect my Trixboxes Trunks together. Can this be done?
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