Yes, that’s on my todo list. It’s pretty easy to add an additional option that selects the last field of the MAC. For now, if you need, you can modify the source code and re-flash. The MAC address is specified close to the top of interval_program.pde. Also, in the past I was able to use multiple controllers (with the same MAC) on the same network by using static ip (each controller is given a different ip). This might depend on your router, but I was able to access each individual controller without a problem.