Spanish to English Art/Literary Poetry & Literature fiction (pastoral)

Hello

In a novel taking place in 1934 in the Pyrenees, the author describes the societal organization in a mountain village whereby a father chooses his heir. The other children, "tiones" are essentially condemned to a life of poverty and hard work and can never have children.

The book is full of sentences along the lines of "cuando pienso en los tiones, se me encoge el alma", etc.

I have managed to find one dictionary that lists "tión" (the author of my text doesn't use an accent in the singular), saying it is short for "solterón", which fits. I had previously been assuming it was more along the lines of "serf" due to the harsh conditions described and the fact that the system is described as feudal.

My question is, presuming that "tion" is "tión" and is indeed short for "solterón", what on earth do I call that? I can't say the "bachelors" make his heart break, etc. But nor can I say "second-born" as it refers to all "non-heir" children, and in this system, birth order is ignored (i.e. the father might choose the third-born, and thus the first- and second- born would both be "tiones").

I may need a neologism, I guess. Any suggestions appreciated!

Many thanks in advance!
xLisa