Upload a file and Add a page invisible for default users in Groups

Hello,

I'm new with Elgg....

thanks to all the documentation, I am well underway...

I only get something not done.

I use the Roles 2.0.0 and Group Tools 5.0 plugin.

In Groups, however, I want the features Upload a file and Add a page invisible for default users.

I have a plugin customizations so I do not work in the core files.

Can someone tell me how and what I should add to get those features invisible?