You can create separate discussion forums for groups of students in a single forum activity (you don't need to create a separate forum activity for each group).
Good practice guides and tip sheets have been developed to support quality in both curriculum design and teaching practice. Good practice guides provide a pedagogical overview and tip sheets provide you with practical strategies and ideas for implementation.
Links to group-related resources are provided below.
Under Common module settings, change Group mode to Separate groups to give each group their own private forum, or Visible groups to create a forum
for each group and allow other groups to view (but not post to)
For the Grouping setting, select the grouping containing the groups you want to use for the forum