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Yes you can create access to parts of your site by creating new groups (groupA, groupB, ect). You can do that through Admin/System/Groups then offer permission to modules based on each group.
The trick is finding a module for news articles that will allow you to give permission to groups by individual articles. Seems like most modules only offer "registered, admin, guest" options for access.
I THINK that there is a download module that allows access to specified downloads by custom groups, this might be an option if you want to offer your articles in PDF download format. There might be news modules that allow access based on custom groups per article, but I have not seen that option in news modules I have looked at.
Otherwise you can use a combo of Cjay Content and Multi Menu. Cjay Content would be used to "wrap" your lesson in XOOPS and multi menu to create custom links per group to access the cjay content wrapped pages by their group/student level. Have I lost you yet