Understanding Society User Support

Hello to everyone, I would like to ask you one clarification.

I am working with all the waves of BHPS + US, and I set the data with a row for each parent-child dyad (parent A-child A, parent A-child B, parent B- child A, ecc). I need to identify when a child move in the parent's household, do you have any clue on how identify this mechanism in BHPS? I think that for US it is ok to use the parentID (when it passes from . to !. this means that a child come into the parents' household) combined with the variable newentrant.

But BHPS apparently does not have a variabile similar to newentrant that I can use. Do you have any suggestion on how tot ackle this issue?

Thanks a lot, best, G