A simpler method of setting up mesh networks for devices such as e500 that doesn't involve creating mesh WiFi master and slave in separate AP groups.
You are currently able to set up mesh in a single AP group using user defined overrides. See below.
wireless wlan 1
mesh ${meshmode=off}
If you have a WLAN template for mesh and ensure that this is WLAN1, this will then allow you to mesh on a single AP group. Whenever wishing to deploy mesh into an AP group, add the mesh WLAN to that AP group. The above will allow you to change the default status of off to BASE or Client when the configuration is pushed down to that specific AP.