How to Block Suggestions for Groups on Facebook
- 1). Log in to your Facebook account.
- 2). Click the "Groups" tab on the left toolbar. A menu will open to display any pending group invitations or suggestions.
- 3). Click "Ignore" on any pending invitations. All new groups created by your friends will follow the current standard for invitations, so after denying these invitations, you will no longer receive group suggestions.
Source...