A system for forming retained container groups from an arrayed container group (ACG) via application of an adapted retainer blank to the ACG is generally provided. The system is advantageously characterized by a container conveyance apparatus for conveying arrayed container groups, a supply of retainer blanks from which retainer blanks are dispensable, and a processing station characterized by a segment of the container conveyance apparatus, a die block, for receipt of a dispensed retainer blank from the supply of retainer blanks, and a robotic arm equipped with an end of arm tool (EOAT). The robotic arm is operable so as to selectively position the EOAT within the processing station, the EOAT positionable for urged engagement of a dispensed retainer blank received upon the die block so as to form and secure an adapted retainer blank, the robotic arm thereafter positionable to register the secured adapted retainer blank with a conveyed ACG conveyed on the segment of the container conveyance apparatus of the processing station, the robotic arm further positionable to apply the secured adapted retainer blank to the registered conveyed ACG to thereby form at least two retained container group packs from the registered conveyed ACG.