You have code that collects joystick positions. You have code to move servos.
Some of the code belongs on the device with the joysticks and a radio. Some of that code belongs on the device with the servos and a radio. The ONLY challenge is determining how to format the data to send and how to use what was sent.
Suppose that you are holding the controller, and your best bud is moving the servos. What do you need to tell him? Or her? Once you've figured that out, formatting the data is easy, after you've decided on text vs. binary.
Once you've figured that out, using the data is pretty simple.
If you have problems, let us know what they are, and what decisions you've made.