It looks like I made a typo in my previous post, referring to the
radio_multi C file (under wixel-sdk\libraries\src\radio_multi) as
radio_link; thanks for point that out. I modified my previous post.
You would need to pass the message to the Wixel from the mbed via serial (pins P27 and P28 on the m3pi expansion PCB), read the incoming data from your Wixel, and pass it to the function
It sounds like you are new to using the m3pi and Wixel, so I strongly recommend reading through the m3pi User's Guide and the Wixel User's Guide before continuing. If you have some code written for your mbed and Wixel, you can post them here, and I would be happy to take a look.