View and post in groups without joining it

Hello,

I am interested in the premium plugin.

I need to know something before. For my personal use case, I need my users to be able to see posts and write posts in groups even if they did not join the group. Is it possible ?

Besides, I would also need to be able to use some groups like this (as describe above) and some groups with the joining option.

Is it possible ?

Thanks you