Open cluster groups and complexes It is generally agreed upon that stars typically form in open clusters and stellar associations but little is known about the structure of the open cluster system. Do open clusters and stellar associations form isolated or do they prefer to form in groups and complexes Open cluster groups and complexes could verify star forming regions to be larger than expected which would explain the chemical homogeneity over large areas in the Galactic disk. They would also define an additional level in the hierarchy of star formation and could be used as tracers for the scales of fragmentation in giant molecular clouds Furthermore open cluster groups and complexes could affect Galactic dynamics and should be considered in investigations and simulations on the dynamical processes such as radial migration disc heating differential rotation kinematic resonances and spiral structure. In the past decade there were a few studies on open cluster pairs (de La Fuente Marcos & de La Fuente Marcos 2009a b c) and on open cluster groups and complexe…