motivations and objectives {#objec}
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The role of large scale mass assembly on galaxy evolution
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In $\Lambda$CDM cosmological models structure formation occurs hierarchically, such that the most massive halos corresponding to galaxy clusters form latest, doubling their masses on average since $z{\sim}0.5$ [@BSW09; @GNF12], and are also the most dynamically immature. Preferentially located at the nodes of the complex filamentary web, clusters are continually accreting dark matter halos containing individual galaxies or galaxy groups. On average, 50% of galaxies in local clusters have been accreted since $z{\sim}0.4$ [@BSB09], of which 40% are within groups [@MBB09].

The process of central galaxies becoming satellites, as their host halos are accreted into more massive halos, has been shown to strongly affect their evolution, with satellite galaxies more likely to be quenched than central galaxies of the same stellar mass [e.g. @WTC12]. Star formation is suppressed within galaxy groups, with the fraction of star-forming galaxies declining steadily with increasing group mass (at fixed stellar mass) and proximity to the group centre [@WVY06; @WTC12; @WDF13]. Galaxies which are quenched within such groups and later accreted into clusters are described as having been ‘pre-processed’.

Numerical simulations and theoretical studies predict the effect of cluster-cluster mergers 