Mesh & Captive Portal

Ok, order my first RouterBoards (433AH) and have configured two mesh units. Each have two wireless cards, 1 for backhaul mesh in the 5ghz range and an access points in the 2.4ghz range for clients to connect to.

What I want to accomplish,
Users that connect to the 2.4ghz or connect via the LAN port of the mesh unit are prompted for a Captive Portal Screen. Then that traffic is sent/routed over the MESH network back to my wired internet connection if they login.

I have followed the wiki and made the captive portal work, also with the wiki got the two units to mesh, and via the wiki I have setup and access point. My biggest problem/question is how do I route the traffic over the mesh? When I connect to the Wireless or connect to the lan I get a DHCP address from the RouterBoard and when captive portal is disabled it will route but I can’t ping the interfaces(wired or wireless) even when I have a valid IP? Not sure why that is.

Client Computer → 2.4ghz → RouterBoard(CaptivePortal) → 5ghz → Routerboard → Internet Connection

I want each Mesh RouterBoard to run a captive portal and only let authenticated traffic onto the MESH.

Is this even possible? or do I just have to run the captive portal where the network connects to the internet?

Thanks,
Erin