If you choose to migrate all group members then every member of this group will become a member of the specified Groove Server ...

If you choose to migrate all group members then every member of this group will become a member of the specified Groove Server 2010 Manager and domain when they next log in to SharePoint Workspace 2010 or Groove 2007 or later. Are you sure you want to migrate all domain members to a new Groove Manager domain?