Once you have defined your requirement, and if Enable Specific Group Requirements is enabled at the Group Type level, you can apply the requirement to individual groups. If you have Administrate access to a group, you'll notice a panel on the edit screen entitled Group Requirements. You can add group requirements from this panel. There is also a setting to keep group members who don't already meet the requirements from being added to a group. NoteLimited RestrictionThis restriction on adding group members only applies to manually adding people to the group. Workflow actions that add someone to a group will still be able to add people who don't meet the requirement to the group.