Guest network BSSID

I appoligize in advance if my search-fu wasn't good enough to find this already answered.

I want to create a guest network with a specified BSSID. The default is 00:00:00:00:00:01 for the first, and I assume it simply increments the least significant bit for the rest.

I've tried using ifconfig to bring it down, change it, and bring it back up. That gives an error message.

I've tried "nvram set wl0.1_hwaddr" followed by a commit, but when the interface comes online it's back to it's...

Guest network BSSID