Union
One of the things that big businesses hate the most is when unions are created for the workers. Unions mean that now the workers are organized and can make demands and get rights that they ask for to protect themselves. It’s a greedy man’s worst nightmare because now he has to look after his employees.
We guess that in this example they are trying to say that the eldest daughters are like the union workers and the parents are the greedy CEOs. We don’t know if that is too harsh of a parallel to make, but it does seem like they should get together and fight for their rights.