Supposedly there are two ways to do this:
Via the wiki page:
Originally Posted by Enworld
Go to the "Options" tab at the top of your wiki page and select "Assign to Social Group".
Doing so gets:
Originally Posted by Enworld
"You can assign the current page to a Social Group whose users should manage the page. Use the form below to locate and select the appropriate Social Group."
But here everything stops. The 'form' does not locate or allow the selection of anything.
Via the Campaign Manager page:
Using the button - Add Content> Add Existing page. Selecting this has no effect. The status bar shows Run script"//"