If you currently have contacts in a Group, Global Update can be used to mark all their records with the Viewable by Group setup above.
1.Click Groups under the Contacts Modules
2.Click Table View so you can locate the group or if you know the Group Id enter this into the Quick Search field
3.Locate the Group of contacts that are to have the Viewable by Group option setup
4.Click Members on the tool bar
This will open all those contacts in the Contact Detail form
5.Click File | Admin | Global Update
6.Locate Record Viewable by Group, click OK
7.Select the Group setup under User Login Accounts, click OK
8.Click Yes to confirm
This inserts the Viewable Group that only certain users can view