  Energy cascades lie at the heart of the dynamics of turbulent flows. In a
recent study of turbulence in fluids with odd-viscosity [de Wit \textit{et
al.}, Nature \textbf{627}, 515 (2024)], the two-dimensionalization of the flow
at small scales leads to the arrest of the energy cascade and selection of an
intermediate scale, between the forcing and the viscous scales. To investigate
the generality of this phenomenon, we study a shell model that is carefully
constructed to have three-dimensional turbulent dynamics at small wavenumbers
and two-dimensional turbulent dynamics at large wavenumbers. The large scale
separation that we can achieve in our shell model allows us to examine clearly
the interplay between these dynamics, which leads to an arrest of the energy
cascade at a transitional wavenumber and an associated accumulation of energy
at the same scale. Such pile-up of energy around the transitional wavenumber is
reminiscent of the formation of condensates in two-dimensional turbulence,
\textit{but, in contrast, it occurs at intermediate wavenumbers instead of the
smallest wavenumber
