Send a file to a specific app

I would like to send a file from my application myApp to two other applications: MyApp2 and myApp3 My files will be sent with a custom extension, such file_to_send.myapp

From the application myApp, after a click on a button, i should see an "Open With..." asking me if I want to open the file with MyApp2 or myApp3 (so I should make sure that the extension ".myapp" is associated only with the MyApp2 and myApp3 applications). Do you know a way to do this?