  Context. Open clusters (OCs) are fundamental benchmarks where theories of
star formation and stellar evolution can be tested and validated. Coma Ber and
Latyshev 2 (Group X) are the second and third OCs closest to the Sun, making
them excellent targets to search for low-mass stars and ultra-cool dwarfs. In
addition, this pair will experience a flyby in 10-16 Myr which makes it a
benchmark to test OCs pair interactions. Aims. We aim at analysing the
membership, luminosity, mass, phase-space (i.e., positions and velocities), and
energy distributions for Coma Ber and Latyshev 2 and test the hypothesis of the
mixing of their populations at the encounter time. Methods. We develop a new
phase-space membership methodology and apply it to Gaia data. With the
recovered members we infer the phase-space, luminosity and mass distributions
using publicly available Bayesian inference codes. Then, with a publicly
available orbit integration code and members' positions and velocities, we
integrate their orbits 20 Myr into the future. Results. In Coma Ber, we
identify 302 candidate members distributed in the core and tidal tails. The
tails are dynamically cold and asymmetrically populated. The stellar system
called Group X is made of two structures: the disrupted OC Latyshev 2 (186
candidate members) and a loose stellar association called Mecayotl 1 (146
candidate members), both of them will fly by Coma Ber in $11.3\pm0.5$ Myr and
$14.0\pm0.6$ Myr, respectively, and each other in $8.1\pm1.3$ Myr. Conclusions.
We study the dynamical properties of the core and tails of Coma Ber and also
confirm the existence of the OC Latyshev 2 and its neighbour stellar
association Mecayotl 1. Although these three systems will experience encounters
we find no evidence supporting the mixing of their populations.
