Request that a coach can only view the progress of his/her students in a sitegroup

First to mention, it's a very nice plugin! I've a request. Would it be possible to show to a coach only his/her students progress(bar)? And not of all students in a specific course of category? I've students in different site groups, and assigned to specific coaches, and I can't see how I can manage this now within the possibilities of the plugin. Under Permissions in Category it's only possible to disable or able it for all students.