  A minimal single-brane holographic model can be used as a dual to 2d
conformal interfaces (ICFTs) to calculate the transmission coefficient
$\mathcal{T}$ of energy transported across the defect as well as boundary
entropy $\log g$, the additional entanglement entropy for some sub-region that
encloses the defect. Both $\mathcal{T}$ and $\log g$ are uniquely determined by
the tension characterizing the brane. In contrast, in field theory defects
typically the transmission coefficient can be dialed from 0 to 1 independently
for each allowed value of $\log g$. To address this discrepancy, we look at a
double brane (3-region bulk) holographic model. Merger of two single brane
interfaces creates genuinely new interfaces which indeed allow a range of
accessible transmission coefficients for a fixed value of $\log g$. In
particular, the $\mathcal{T}=0$ limit of two completely decoupled BCFTs can be
achieved.
