Polymorphic XML Binding with JAXB

Here is what I am trying to do:

XML is this:

<Doctype1>
    <Outter>
        <Inner>
          <ProblemType1>somedata</ProblemType1>
        </Inner>
    </Outter>
</Doctype1>

<-- However, I have: -->

<Doctype2>
    <Outter>
        <Inner>
          <ProblemType2>somedata</ProblemType1>
        </Inner>
    </Outter>
</Doctype1>

and Share most of the same fields, but in the case of Doctype1 I need ProblemType1 and in Doctype2 I need problem 2.

I want to be able to reuse the classes I bind to for and as they are a common tag across all doc types.

@XmlAccessorType(XmlAccessType.FIELD)
public class Doc1{

    @XmlElement(name = "Outter")
    public List<Outter> outtards;

}

@XmlAccessorType(XmlAccessType.FIELD)
public class Outter {

    @XmlElement(name = "Inner")
    public List<Innard> innards;
}

@XmlAccessorType(XmlAccessType.FIELD)
public class Innard{

    // need to change this if it's Doc1 or Doc2. The element name won't change
    @XmlElement(name = "Inner")
    public ProblemType1 subtype; 
}

It seems like Maybe a factory is in order?

@XmlType(factoryClass= , factoryMethod=)