My understanding is no, you can't do this with installment credit. It would have to be a re-fi with both of you on it, and they'd go with your scores, assuming that they're lower. AU's only work with revolving credit (i.e., CC's), and not all of them report AU cards. And even then, we don't know if Experian still credits them, since we haven't been able to access our EX FICO's in nearly two years, so we don't have any feedback as to whether they're being scored.
I will gladly accept any correction on this from those with personal experience in this area! 