Closest thing I see in the WNR3500 documentation is the feature they call "Push 'n' Connect"... but unless I'm misunderstanding how this feature works, it still appears to require that you use a web browser to log in to the router's admin interface each time you want to add someone. This kind of defeats your "avoid spending social time on technical support" requirement. Futzing with the router's admin screens is probably about as much work as helping someone configure the WiFi SSID and password into their device...
WNR3500 Manual wrote:
1. Log in to the wireless router at its default LAN address of http://www.routerlogin.net
with its default user name of admin and default password of password, or using whatever LAN address and password you have set up.
2. On the wireless router main menu, select Add a WPS Client (computers that will connect wirelessly to the wireless router are clients), and then click Next. The Add WPS Client screen displays.
3. By default, the WPS button is selected. Either click the onscreen button, or press the WPS button on the side of the wireless router. The wireless router tries to communicate with the client for 2 minutes.
4. Go to the client wireless computer, and run a WPS configuration utility. Follow the utility’s instructions to click a WPS button.
5. Go back to the wireless router screen to check for a message. The wireless router WPS screen will display a message confirming that the client was added to the wireless network.
: One other thought -- if you're willing to run two Ethernet cables between the closet and the counter, you can still do it all with just the one router (plus a switch in the closet). As I mentioned previously, multiple router setups will require manual configuration to prevent conflicts. Just trying to save you some potential hassles...