P2P in libxDot uses a different sync word from those used with LoRaWAN. The P2P packets will be filtered just as with Private/Public network LoRaWAN packets are.
Also the P2P mode uses an IQ setting same as a gateway transmission. This allows the Dots to received each others packets, but will not allow a gateway to hear them, just as gateway packets are not received by other gateways.
The packet forwarder could be modified to support this type of operation.
The IQ setting would need to be reversed and sync word changed to 0×56.
These resources can help you if that is something you are willing to endeavor.
https://github.com/Lora-net/packet_forwarder
http://git.multitech.net/cgi-bin/cgit.cgi/meta-mlinux.git/tree/recipes-connectivity/lora?h=3
http://www.multitech.net/developer/software/mlinux/mlinux-building-images/
http://www.multitech.net/developer/software/mlinux/mlinux-software-development/mlinux-c-toolchain/