The attached file is an example of the network i have setup. Right now only one of the 2.4GHz wireless NICs are enabled and setup for PPPoE. I would like to run one PPPoE server for both 2.4GHz interfaces and at the moment I cannot think of a solution. If anyone has an idea I would be grateful for a reply.

Bridge your wireless interfaces with the same value of horizon and set your PPPoE service to bridge.
leave the PPPoE Access Concentrator at the place of your Internet Connection.
Use a VPLS or EoIP Tunnel to transport PPPoE to the Customer.
This method allows for a much better scalbility, if you decide to expand you services.
let the PPPoE-Server serve to a bridge
add the EoIP-Tunnel interfaces facing to your wireless interfaces to this bridge.
Also add to each wireless interface one EoIP-Tunnel interface.
This way, only PPPoE leaves the AP. No Management packets or internal networking leaves the AP, if configured properly.
you should consider full user isolation:
you need to create one PPPoE-Server for each EoIP-Tunnel and also disable default forwarding on your Wireless APs.
Full user isolation is really important with PPPoE-setups, because it is VERY easy to sniff the user credentials from other users.
“Full user isolation is really important with PPPoE-setups”
how can isolation???
tnx @sup5
you need to create one PPPoE-Server for each EoIP-Tunnel and also disable default forwarding on your Wireless APs.