WiFi router using another WiFi network to reach Internet

Is there an off-the-shelf way to create a private WiFI network (with firewall to block inbound connections), which uses another WiFi network to connect to the Internet? This sounds like a WiFi Extender , but I read Does a Wi-Fi range extender create a separate network? and it seems to say that most extenders are a strange hybrid, where the NAT address ranges must be disjoint and clients of the extender are directly addressable from upstream, which I do not want. . Do there exist WiFi routers with two radios,where one can be used for the Internet uplink ? I need the exact equivalent of connecti

Question by jimav on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.