You might want to look at this post regarding the Allen&Heath QU24. I believe the project file there has some MUTE Group and even fader examples. Coupled with the documentation on your specific mixer from Allen and Heath, you should be able to figure the translations you need.
For a more specific example, I would need to know what the AXE FX3 sends for the specific function you require. It is beyond the scope of providing a complete solution for free support here, but I could give you a specific example to get you started as part of the free support service. I don’t have a QU16 for testing so would need to rely on the accuracy of the documentation.
Steve Caldwell
Bome Customer Care
Also available for paid consulting services: bome@sniz.biz