As the title suggest, I've created several groups inside Saleforce but when I add a Navigational Item of Object Groups doesn't show any record.
I have followed these instruction but nothing happens,
Groups in Salesforce are separated and not sharable to be a group in Communities. You must create a group in Communities for it to show up in Communities.
There is already an idea posting about this: https://success.salesforce.com/ideaView?id=08730000000kwkzAAA