For most Central American cichlids, no more than a pair of a single species, per 6 ft tank as adults, are feasable.
So it is no surprise that the beanii were killed by the trimac
Where Mayaheros beanii come from on the northern Pacific coast of Mexico they are the sole cichlid in the habitat, and each pair might occupy 1000 gallons, so they are not equip to deal with another species.
I have kept all the above cichlids, but would never keep them together in the same tank '



Trimacs do not share habitat with beanii, so trying keep them together is problematic, they are from a totally different region on southern Mexico.
Same withh Mesoheros festae, from west of the Andes in South America. They are basically loners and seldom come close to sharing habitat with any other cichlids.
Where I live now, in stretches of rivers like the one below, I usually find only 2 species of cichlids, and their microhabitats are in totally different zones of the river, so territories don;t collide.

One species inhabits sandy areas with mederate flow, while the other rocky habitats with higher flows, they seldom come into conflict with each other.
So when we consider cichlids in the confines of the limited space in an aquarium, its no surprize, they kill each other.
I am sometimes amazed when they don't.
On Saturday I visited and collected in the Rio Indio where I only found 1 species of cichlid, among schools of tetras.
