Many complex systems are modeled by a network of different subsystems, each having their underlying mathematical model representations. Energy-based modeling of each of these subsystems can yield a port-Hamiltonian (pH) representation. In this paper, a single-phase flow model, a dissipative mathematical component and a two-phase flow model are interconnected to model hydraulics for Managed Pressure Drilling (MPD) applications. These subsystems are interconnected in a power-preserving manner to build an aggregated pH system for real-life MPD scenarios. We prove that the interconnection junction connecting the single-and two-phase flow models is conditionally power-preserving.