Bind user to MAC address

I have a small network with a handful of users and no central authentication. Any given device belongs to a specific user and is not shared. I would like the Sophos XG to bind each user to their device, preferably by MAC address.

There is "MAC Binding" under the user, but it's for limiting users to specific MAC addresses, not binding a MAC address to a user.

The desired outcome is that when I look at the "Current Activities" i can see which user is generating the traffic, so if there is another way of getting this information into that screen then that will suffice.

Thanks

James