Moodle 2.5 Group enrollment process
If you are using Moodle to create a blended or online course but teach multiple sections of the same course throughout the year, you will probably want to set up separate groups for each section (or class hour) to facilitate group specific forum discussions, assignments, and for querying grades and user reports by class hour. The video tutorial and step-by-step guide below will help you set up your groups and group enrollment codes. Note: This process should be completed prior to enrolling students. A separate process is needed for manually sorting students into groups who were enrolled manually or through course self enrollment.
Watch the Video here - http://goo.gl/cXBpLW
1. In the Administration block choose to Edit settings
2. In the Groups section, select Separate groups
3. Set Force group mode to Yes and then Save your changes