I don't know if it's a first here; I hope someone will. European companies have ranks such as first soloist, second soloist, coryphee (the Royal Ballet is one). And Paris makes a distinction between etoiles and premiers danseurs -- and THEN you get to the soloists.
During the Romantic Era there were even more ranks -- whether you were in the first, second or third quadrille of the corps de ballet mattered. And certain groups had certain privileges -- if you were a coryphee, I believe (I'm writing this from memory, so if someone wants to look it up and finds this is wrong, please feel free

) you couldn't be made to dance in a group larger than eight.
Interesting move for Houston to make -- especially when they seem to be turning way from the Stevenson model of mostly full-length ballets (where such ranks might be useful) to the new! contempo-ballet model, where most of the ballets are danced by no more than a dozen dancers, and it doesn't matter what rank they are!