PeepSo bbPress addon enables you to attach groups into the forum. To enable the setting to navigate to
PeepSo Configuration >> PeepSo bbPress Addon > Group Forum Settings Panel
with this feature, When users join a group, they get automatically assigned to a relevant forum. Those forums can be private too, meaning those forums will be available to the people who actually joined the group. This feature requires PeepSo Groups Plugin to be enabled.
To assign a group into the forum, Simply Navigate to
Forums >> Add New Forum >> PeepSo Groups Panel and assign a group
when a user will join this group, He will automatically be joined the respective forum and can view that frm tab in the group.