I’m not sure if there is a way to fill the selection field doing it this way, so maybe I’m wrong, but I would set the on_change on the one2many field, and iterate all the rows, setting the value for the attendants_relation field when it is needed.
I’m not sure if there is a way to fill the selection field doing it this way, so maybe I’m wrong, but I would set the on_change on the one2many field, and iterate all the rows, setting the value for the attendants_relation field when it is needed.