Sibling Group Posted on 21st December 20157th May 2021 by ThePD (The Project Definition) Sibling Group is one of two or more individuals having a set of time series in the value taken by the frequency dimension. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Business and tagged analysis. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.