Need help with getting two mt4's to talk to each other

 

What im doing is ruinning an alert indicator on two mt4's and when this alert indicator finds a buy or sell setup what i want it to do is to check with the other mt4 to see if it also has the same buy or sell setup. My question is what is the best way to go about this? I was thinking maybe have the alert indicator write the trade info and time to a file and have a separate program continuously monitor the file to see when both mt4s have wrote the same info and time for a particular trade. In general im just kinda confused as to how it would be best to pull something like this off. Any suggestions would be appreciated.