Synchronizing Team Membership with Updated User-defined Groups
The recommended practice for defining groups is to define them at the organization level whenever possible and then use the user-defined groups in product, library, program, and project teams. The Organizations 
> page can be used for this purpose.
> page can be used for this purpose.Over the life of a product, library, project, or program, the members of user-defined groups referenced in teams may change. If group membership is modified from within Windchill, the membership of the teams in which the group is a member is automatically updated and you do not need to do anything additional; however, if the membership of one or more groups is modified using a third-party LDAP tool, you need to put together a plan for how to remove the updated groups from the participant cache and synchronize the teams on a regular basis.
For details on your options, see Synchronizing Teams with User-Defined Groups.