You can share activities with a group both from your My Groups page and from your activity list.
Select Community > My Groups. The My Groups page will open, showing thumbnails of all the groups you have joined.
Select the thumbnail for the group to which you want to add activities. The page for that group will open.
Select Add Activity.
The Add Activities dialog will open, displaying thumbnails of all the activities on your activity list.
Select the check boxes next to the activities you want to share.
Select Add to Group.
From Your Activities List
Select the title or thumbnail of the file you want to share. The activity detail will open.
Select the Add to Group button (circled in the illustration above). The Add to Group dialog will open.
Select the check boxes next to the groups with which you want to share the activity.
Note: You can also share an activity with a group at the time you upload the file. In the Add this file to the following groups section at the bottom of the Upload Your Activities page, just select the check boxes next to the groups with which you want to share the activity.