No editing access

This look like a helpful plugin but its not working for me. I’ve created a group and set all those with ‘Author’ role to the group.

I’d like members of that group to be able to edit certain page so have set everyone to access the page the only group users to edit.

But when I log in as a group user I don’t have editing access.

Any ideas?

The idea is that I don’t want these users to be able to edit other pages.

p.s. don’t want to use role scoper if possible.

https://www.ads-software.com/extend/plugins/user-access-manager/