Hello Aasif Bashir Dar.
It is related to cryptography and i want to see if it can be done here. I am not sure if we could use two modulation schemes at the same time for two different signals. I am mainly focusing on the add component because there we could readily add another signal. I tried to change the modulation scheme but i guess it changes globally hence changing the scheme for overall system.
Regards
Atul Sharma