I have found good success with the plugin Virtualgroup. I don't have write access to AD so in my case making AD group changes requires approvals, other people getting involved, etc.etc. yucky poopoo red tape. With Virtualgroup, I can set up my own access groups, and assign these virtual groups to wiki pages/namespaces, all within the Wiki Admin. Much easier.
https://www.dokuwiki.org/plugin:virtualgroup