Fodsports intercoms of different models can be paired.
But the software of different models is not the same. So there might be some incompatibility problem if different models are paired together.
Generally, the FX8 series(FX8, FX8 Pro, FX8 Air) and M1-S series can pair together and support 2-10 riders intercom.
Besides, the FX6 and FX6 S can also pair together and support 6 riders group intercom.
For other models, if paired with a different model, they can only get an one-to-one communication.
If you want a stable group intercom, you can choose the same model with your friend. Or choose the model that is compatible with theirs.