Multiple Access Points - Same SSID (Complicated Setup)

Question

My current network utilizes WPA2-Enterprise as its authentication method. I am trying to extend my network further, but most wireless routers that I have found don't support repeating a WPA2-Enterprise signal. So, therefore, I purchased an ASUS EA-N66 to use as my receiver. And, that has worked pretty successfully so far with just a router connected to it. However, I now want to add another AP using the same SSID and same authentication server where it currently lists as (Additional AP). My question is how does the Additonal AP now differentiate which network to connect to, the Wireless AP/Router vs Additional AP? My concern is that it will form a loop and then never connect to anything.

My (target/current) network topography looks like this:

                  RADIUS Server
                       ^
                       |
                       |
Internet  --> Wireless AP/Router <-(WPA-2 Enterprise)-> EA-N66 ----> Router
                                                                        |
                                                                        |
                                                                        |
                                                                 (Additional AP)

Is there something I should be doing specifically to mitigate this problem? Or is there any existing technology that already allows it to avoid this problem?

Previous Research: I have referred to "How can I get the same SSID for multiple access points?" however it does not exactly fit into my problem.