Would it ever be possible to whitelist URLs in Captive Portal, for example someone having a page info.clientsurl.com in which they host a page with internal information: dinner menu, activities for today ... without links to other URLs
I saw that this was just asked in github but i would ask to you if it would be integrated in newer versions.
Nobody of the team?
You cannot, it is only possible to whitelist ip addresses. If you want to filter stuff on layer 7, you need a proxy or DPI.