Keep public hotspot enabled when using third party router
I switched my BT Hub 4 for a 3rd party router (mini PC with pfSense installed) some time ago. I've kept the BT hub as an access point, with the firewall and dchp server functions disabled.
In the current configuration, the BTWIFI public hotspot no longer exists. I'm interested to see if there's any way of enabling it whilst still using a third party router for my private internet traffic.
I presume the hotspot traffic is normally routed via a hidden VLAN over the WAN connection, or something like that? Could I maybe separate it out with a switch before the router? Or is there a way of passing it through the router to the BT Hub?