Group Build functionality in PeopleSoft HCM can be used to group employees together based on flexible parameters. But, one limitation of Group Build is that it does not consider future effective dates, even if the parameters used to build the Group is designed to return future effective date. As mentioned in support.oracle.com (or customer connection or metalink, whatever you might want to call!), Group Build is designed to only consider current and historical effective dated rows. This is an important point to keep in mind while designing any process that involves Group Build - "Group Build does not consider future effective dates".