Accessing password protected wifi with access point

[Andy T]

I have the following scenario:
We have guest wifi access that requires you to enter a password (which we have) from the browser in order to use it.
I also have a network appliance that needs to be plugged directly into the router (to which I don't have physical access).
Is there a way to use an older WiFi router or another device to connect to the guest wifi access, and supply the password so that all devices that plug into/connect to the signal of the devices are authorized?

 

[JackMDS]

Through Networks/Interent you can in access any Networking device in the world provided you know how it is configured and have the credential to do so.

There is info in your post to understand what specifically you have and what to do with it (and it seems that you have No authentication to do it).