Android to Android USB communication

Hello,
I'm trying to make an application communicate on Android: I connect both Android devices with an USB OTG cable (the host one will need to support OTG).
Is there any way I can make my application, running on both Android devices, communicate?
For example, how can I send a message from a device and show in on the other one? Could the communication work both ways?
If so, how?
Is it possible to override the default "File Storage" function?

Any hint is appreciated.
Thanks!