On a problem related to homomorphism groups in the theory of Abelian groups

In this paper, for any reduced Abelian group $A$ whose torsion-free rank is infinite, we construct a countable set $\mathfrak A(A)$ of Abelian groups connected with the group $A$ in a definite way and such that for any two different groups $B$ and $C$ from the set $\mathfrak A(A)$ the groups $B$ and $C$ are isomorphic but $\operatorname{Hom}(B, X)\cong\operatorname{Hom}(C, X)$ for any Abelian group $X$. The construction of such a set of Abelian groups is closely connected with Problem 34 from L. Fuchs' book “Infinite Abelian Groups”, Vol. 1.