We investigate the orthogonality preserving property for pairs of mappings oninner product $C^*$-modules extending existing results for a singleorthogonality-preserving mapping. Guided by the point of view that the$C^*$-valued inner product structure of a Hilbert $C^*$-module is determinedessentially by the module structure and by the orthogonality structure, pairsof linear and local orthogonality-preserving mappings are investigated, not apriori bounded. The intuition is that most often $C^*$-linearity andboundedness can be derived from the settings under consideration. Inparticular, we obtain that if $mathscr{A}$ is a $C^{*}$-algebra and $T,S:mathscr{E}longrightarrow mathscr{F}$ are two bounded ${mathscr A}$-linearmappings between full Hilbert $mathscr{A}$-modules, then $langle x, yangle= 0$ implies $langle T(x), S(y)angle = 0$ for all $x, yin mathscr{E}$ ifand only if there exists an element $gamma$ of the center $Z(M({mathscr A}))$of the multiplier algebra $M({mathscr A})$ of ${mathscr A}$ such that$langle T(x), S(y)angle = gamma langle x, yangle$ for all $x, yinmathscr{E}$. In addition, we give some applications.
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