Group is an object container designed to handle a fragment of a molecule, a residue of a protein, a mero of a polymer chain, or other chemical species. Group objects can contain an unlimited number of other chemical species as groups, atoms, and related objects as texts, orbitals, directions and planes. A group is therefore a recursive object, with unlimited nested levels, and its properties should reflect the child chemical features. For example, an amino-acid has amino NH2 and carboxylic acid COOH groups, the later in turn contains an hydroxyl group OH. The low-level engine infra-structure required to implement group objects is fully implemented. Mechanisms to measure length, angle and torsion measurements in groups of atoms are already in place and tested. Algorithms and tools to modify length, angle and torsion values, in both open and cyclic structures have been implemented and fully tested. Everything else is not done yet.