Unmarshalling XML Fragments at multiple levels of a hierarchy with JAXB - jaxb

Question

I need to un-marshal multiple objects out of an XML Structure that looks like this:
<Control>
<TotalCompanies>2</TotalCompanies>
<TotalSales>100</TotalSales>
<Company>
<Name>ACME Ca</Name>
<TotalSales>70</TotalSales>
<TotalSalesPeople>2</TotalSalesPeople>
<SalesPeople>
<SalesPerson>
<Name>John</Name>
<Sales>40</Sales>
</SalesPerson>
<SalesPerson>
<Name>Joe</Name>
<Sales>30</Sales>
</SalesPerson>
</SalesPeople>
</Company>
<Company>
<Name>ACME Va</Name>
<TotalSales>30</TotalSales>
<TotalSalesPeople>1</TotalSalesPeople>
<SalesPeople>
<SalesPerson>
<Name>Janet</Name>
<Sales>30</Sales>
</SalesPerson>
</SalesPeople>
</Company>
</Control>
I need to be able to separately unmarshall a Control object that contains just the totals and not it's children, and similarly I need to do the same thing at the other levels of the hierarchy. So ideally, my beans would look something like this:
class Control {
int totalCompanies;
int totalSales;
}
class Company {
String name;
int totalSales;
int totalSalesPeople;
}
class SalesPerson {
String name;
int sales;
}
I'm doing this in the context of Spring Batch, but I am pretty sure that doesn't matter. If I restructure the XML some, then I can get it to work (I am pretty sure I won't be allowed to restructure the XML, though). That is, if the objects aren't nested, then it is fine. Similarly, I can get all the SalesPeople out pretty easily.
I can also get the entire tree as an object, and that might work in some cases. However, the real incoming file could be larger than the available memory, so that won't work in practice.
Is there any way to get JAXB, or some other out-of-the-box unmarshaller to do this or do I just need to roll my own based on SAX or STAX?
EDIT:
The system is using Spring Batch to read in large incoming files. The files are not as described above (domain is different), but the structure is the same. The architectural direction is to attempt to use out-of-the-box readers (StaxEventItemReader, e.g.) and unmarshallers (Jaxb2Marshaller, e.g.).
The system will operate in environments where we cannot absolutely guarantee there is sufficient memory to hold the entire file in memory.
I have approaches (custom Stax reader/pre-processing the file/requesting an XSD change) that work, but I wanted to make sure I wasn't missing a feature in the standard reader / unmarshaller implementations that could make this work easily out of the box.