No, they could literally not send on the frequencies they listen on in case of FDD. Enabling this would require extra radio hardware. Also there would need to b

No, they could literally not send on the frequencies they listen on in case of FDD. Enabling this would require extra radio hardware. Also there would need to be a some kind of encryption key exchange between devices which is not needed in the centralized setup. They could not easily route to one another without adding extra stuff.