  We introduce a method to distribute memory effects among different subspaces
of an open two-qubit system's state space. Within the linear optical framework,
our system of interest is the polarization of two photons, while the
environment consists of their frequency degree of freedom. By exploiting
initially correlated frequency distributions and initial frequency-dependent
phase factors, we are able to control all the four decoherence functions for
polarization -- corresponding to different open system subspace divisions --
almost independently of each other. Hence, our results demonstrate how, in a
multipartite dephasing system, Markovian and non-Markovian dynamics can be
arbitrarily divided between the subsystems, and giving rise to a novel concept
of memory partitions. We also discuss further implications the results have,
e.g., on the dynamics of purity and entropy within the two-qubit system.
