Hello.
Currently two-way one-to-many communication and frequency changing is not supported by the Wixel SDK. It should be possible though. Jim Remington made a Spectrum Analyzer app, that changes its channel frequency. Take a look at that to see if it is helpful to you, and if you have specific questions, please ask them and we will try to help.
Unfortunately, I do not know how long it takes the Wixel to change channels, David will be back on Tuesday, and he would have a better idea.
- Ryan