  We report on the study of cleaved-edge-overgrown line junctions with a
serendipitously created narrow opening in an otherwise thin, precise line
barrier. Two sets of zero-bias anomalies are observed with an enhanced
conductance for filling factors $\nu > 1$ and a strongly suppressed conductance
for $\nu < 1$. A transition between the two behaviors is found near $\nu
\approx 1$. The zero-bias anomaly (ZBA) line shapes find explanation in
Luttinger liquid models of tunneling between quantum Hall edge states. The ZBA
for $\nu < 1$ occurs from strong backscattering induced by suppression of
quasiparticle tunneling between the edge channels for the $n = 0$ Landau
levels. The ZBA for $\nu > 1$ arises from weak tunneling of quasiparticles
between the $n = 1$ edge channels.
