pfSense

It is better that pfSense can provide an option to allow user to configure the (SSID) part after the MAC address in Called-Station-Id attribute.

I use 2.8.1 CE now, checked the radius packet, the "Called-station-id" in AccessRequest packet from pfsense captive portal is like this now, we assume the hostname of pfsense box is "pfsense.internal".

ab-cd-e5-b3-f9-35:pfsense.internal

It is good, contains the MAC address of pfsense and the hostname of pfsense box, separated with a ":", but it can be better.
as RFC3580 said, if the SSID is known, it should be appended to Called-Station-id.
so it is better that we can configure the latter part of this attribute base on the captive portal profile.

for example, I hope we can configure it to SSID1 for captive portal zone 1, then the value of called-station-id attribute will be this for zone 1:
ab-cd-e5-b3-f9-35:SSID1

and SSID2 for zone 2 if it is another Wi-Fi SSID:
ab-cd-e5-b3-f9-35:SSID2

In this way, it can work with some RADIUS server which can process the access request base on the SSID name.