Page/post restriction based on LDAP groups.

Any update?

I would suggest creating some user meta whenever an LDAP user logs in. You can use the authorizer_allow_login filter hook to inspect the data retrieved from LDAP during a successful login. See:
https://github.com/uhm-coe/authorizer/blob/fd8b2840596870f0486d40e25a3eeb92481002a3/readme.txt#L458-L475

You can use the authorizer_additional_ldap_attributes_to_retrieve filter if needed to add the appropriate LDAP attributes to expose group membership. See: https://github.com/uhm-coe/authorizer/pull/94

Then, in your page or post templates, you can check for this user meta value and determine what to render (the page content, a login message, or perhaps an “unauthorized” message; up to you).

Hope that helps!