Add site members to a specific group.
For SECRET groups, group admins and group members can add additional members to their group.
For PUBLIC and PRIVATE groups, only group admins can add additional members to their group.
They can also allow all group members to add a new member to the group with group.settings.
Group ID.
Member IDs. See the Members API for details.
This method doesn’t return any custom errors, but may return standard errors. Learn more about standard Wix errors.