Instead of having them abduct only woman or the overused orphans how about them having abducted a freshly married couple. The barbarians saw potential in the husband (and/or wife if gender equality is a thing in your setting) or maybe he/she is distant relatives from one of the founders of their tribe etc. So the barbarians would offer them to join them if he/she is strong enough for being a guardian. That is determined by a series of tests, one requiring a vision quest under a new moon which is still a few weeks away. Until then the couple stays with the barbarians. If the trials are failed both would have been returned to the village but the PCs show up before that.