You actually can nearly do that. Facebook inexplicably showed me how a few weeks ago. If a friend reshares something, you’ll see it, but it removes all groups, etc. It was stunning how little content actually comes from friends.

On the Facebook site (I’m sure it can be done via app, too, but I didn’t look), click on the menu near the top right, then click Feeds (under Social). Then click on Friends on the left.