  This paper reports the discovery and orbital characterization of two extreme
trans-Neptunian objects (ETNOs), 2016 QV$_{89}$ and 2016 QU$_{89}$, which have
orbits that appear similar to that of a previously known object, 2013
UH$_{15}$. All three ETNOs have semi-major axes $a\approx 172$ AU and
eccentricities $e\approx0.77$. The angular elements $(i,\omega,\Omega)$ vary by
6, 15, and 49 deg, respectively between the three objects. The two new objects
add to the small number of TNOs currently known to have semi-major axes between
150 and 250 AU, and serve as an interesting dynamical laboratory to study the
outer realm of our Solar System. Using a large ensemble of numerical
integrations, we find that the orbits are expected to reside in close proximity
in the $(a,e)$ phase plane for roughly 100 Myr before diffusing to more
separated values. We then explore other scenarios that could influence their
orbits. With aphelion distances over 300 AU, the orbits of these ETNOs extend
far beyond the classical Kuiper Belt, and an order of magnitude beyond Neptune.
As a result, their orbital dynamics can be affected by the proposed new Solar
System member, referred to as Planet Nine in this work. With perihelion
distances of 35-40 AU, these orbits are also influenced by resonant
interactions with Neptune. A full assessment of any possible, new Solar System
planets must thus take into account this emerging class of TNOs.
