  In this paper we consider a simplest two-dimensional reduction of the
remarkable three-dimensional Hirota-Ohta system. The Lax pair of the
Hirota-Ohta system was extended to a Lax triad by adding extra third linear
equation, whose compatibility conditions with the Lax pair of the Hirota-Ohta
imply another remarkable systems: the Kulish-Sklyanin system (KSS) together
with its first higher commuting flow, which we can call as vector complex MKdV.
This means that any common particular solution of these both two-dimensional
integrable systems yields a corresponding particular solution of the
three-dimensional Hirota-Ohta system. Using the dressing Zakharov-Shabat method
we derive the $N$-soliton solutions of these systems and analyze their
interactions, i.e. derive explicitly the shifts of the relative center-of-mass
coordinates and the phases as functions of the discrete eigenvalues of the Lax
operator. Next we relate to these NLEE system of Hirota--Ohta type and obtain
its $N$-soliton solutions
