We want each group to have one panel node (that is, a node which content type is "Panel"). The group administrator can then use different kind of layouts and display existing content.
I created two groups A and B. I also created panel node (a node which content type is "Panel") for each group and some nodes that belong to group A and some nodes that belong to group B
Now, when admin of group A edits the panel node's content (through a tab "Panel content") of group A and selects Existing node when adding content to a panel pane, he can choose nodes that belong to group B. Is there a way to make panels respect OG access control? So that group A admin could not select contents of group B to be displayed in a panel pane of group A.
The content in the groups still need to be public so that if anonymous user visits content belonging to each group he will be able to see them.