Control many devices via Wifi
Yes, I agree with @Paulo Soares to use 2 Arduinos.

It makes little sense to make the 2nd wireless jump between the 2 Arduinos using a complex packet protocol such as TCP/IP.  This project uses 2 Xbee radios.  I suspect it is also possible to accomplish this using COTS model airplane radio.  This may be talked about here but it is not clear if the hardware talks to existing R/C hardware or to proprietary hardware.