Zero morphism $0_{XY}$ is defined by the formulas $a\circ 0_{XY}=b\circ 0_{XY}$ and $0_{XY}\circ c= 0_{XY}\circ d$ for every morphisms $a$, $b$, $c$, $d$ of suitable sources and destinations.
I define a partially ordered category as a category with a partial order on each of its Hom-sets, such that
$f_1\le f_2\wedge g_1\le g_2 \Rightarrow g_1\circ f_1\le g_2\circ f_2.$
My question: Is there any connection between zero morphisms and minimal morphisms of a Hom-set? Do they imply each other? Do they imply each other under some additional conditions? Maybe an implication in one or the other direction works?
So: Under which conditions zero morphism and minimal morphism of a Hom-set are the same?