TOI-187 system and Saturn and Uranus moons comparison

 

Hypothesis: here are three examples of what started out as an ensemble of 6 related stars. Three different kindred sextets. Uranus has one missing moon, which is now broken into smaller pieces, found as irregular moons nearby. A host star goes on the left for the TOI-187 exoplanet system, former host star goes on the left for Saturn and Uranus moons. You can see how they are smaller on the left from proximity to the host star.

In each ensemble, all 6 star members could have ignited at roughly the same exact time. The energy from a pair igniting can affect nearby pairs, and gravity will keep partners close by for the most part.

Stars form in pairs like peas in a pod, with the closest ones most commonly grouping together as gravitationally bound pairs of pairs, or three pairs, or sometimes four. This is not to say we should only expect to ever see quartets, sextets and octets, but they are very common in systems that we have observed, and quartets and sextets are common in our solar system. For larger more compact star clusters there could be much larger related ensembles.