Lopy to Lopy communication issue

[sita]

Hello all,

I have done lopy to lopy communication using https://docs.pycom.io/. But i got some problem that my friend also doing same project in my place, i am receiving signals from my friend's device. How to add device ID so that i will data particularly from my device.
I am new to pycom devices,I tried all the ways but not getting any solution.