I am looking for a (preferably economic or environmental) force/system that would every few months or years force a random sample of the middle/lower class of an area to migrate away. This would be taking place in a mildly dystopian, realistic world set in either current time or within a hundred or so years.
The goal of this is to create groups of people who come together for a short-ish amount of time and are then forced apart. This is seen as quite devastating, but a part of life. Families may only stay together for a few years, spending your whole life with them would be hugely lucky.
My thoughts first go to some sort of seasonal resource gathering, but what stumps me is the necessity that only certain random people from the groups need to go to the new place. It would be no trouble for these people to be in some sort of indentured servitude to massive corporations that force the migration, but what would be the benefit of moving a random group of your workers to a new location when they would know that keeping families together would improve morale and thus productivity?
I appreciate any help in sketching a system where this would be possible