I was wondering if some of the group gurus

At the moment, we have courses which consists of a number of topics, or sessions as we call it. Each session contains course notes, handouts, a quiz and a discussion forum. This pattern is replicated through the sessions.
As part of the assessment for the course, marks are given for contributions to discussion forum topics, as well as written assignments and the online quizzes. I have attached an image showing what this structure looks like.
Our numbers have increased dramatically and will keep on increasing into possibly a couple of hundred, and one way I thought we may best be able to manage a large class size like this, especially relating to forum management, is to use groups. My thinking is to create a number of discussion forums for the same topic, and allocate a forum to a particular group, say of 25 or 50, but give everyone access to the course notes information.
At the end of the day, I need to come up with a better way of managing larger numbers, particularly as it relates to forum, but also generally. We are currently working on a tutor to student ration of 1:25, but could go as high as 50 depending on the course.
Any advice anyone could give to us around managing these larger numbers would be greatly appreciated.
Regards,
Grant Beevers