Needing to encrypt plain sight information
The answer in the comments from dchest is probably the most standard. Encrypt the page with a single, random key. Then encrypt that key for each user using the shared secret that you hold with that user.

It is unclear whether this meets your needs as it is unclear exactly what your needs are.

With that in mind, a fairly advanced way you could get the functionality you require is with Ciphertext-Policy Attribute Based Encryption. It is very complex and would require a lot to describe in this answer (and I don't even know if it meets your needs as they seem to not be fully defined at this point).