Gruppe Sechs (or Gruppe 6) is a security company featured in Grand Theft Auto III,Grand Theft Auto: Vice City, Grand Theft Auto: Liberty City Stories, Grand Theft Auto: Vice City Stories, Grand Theft Auto IV and Grand Theft Auto V. The company uses the Securicar vans to transport goods or money. This company does not appear in Grand Theft Auto: San Andreas but companies called Chuff Security Co. and Lock and Load Security appear on the Securicar instead.
The "Gruppe Sechs" name (German term for "Group Six") is a German language pun on both the infamous European security company Group 4, and the phrase "group sex". In GTA IV, the name is changed to "Gruppe 6" but the vehicle still features "Gruppe Sechs" in much smaller print on various surfaces. The name of the van, Securicar, seems to also serve as parody to Group 4 since they were formally known as Group 4 Securicor. Despite those references, the company can be seen as the equivalent to American security companies such as Brinks based on their very similar vans in GTA IV.
As indicated by markings on the GTA IV rendition of the Securicar, Gruppe Sechs is claimed to have partnered with the Bank of Liberty, and is "licensed and authorized" by the Liberty City Police Department to use deadly force.
The Gruppe 6 headquarters are located in Leftwood, Alderney on Long John Ave, directly opposite to the Westdyke Memorial Hospital. However, no Securicars can be found there on any of the various parking lots.