XML : Can I split marshallering phase to generate DOM Tree

I have to generate a file Xml using Dom.

When invoke (using 4gb) method Marshaller.marshal(Object obj, Node dom) I get error about out of memory.

If I try to generate DOM tree with 8gb it works.

Do you know if exists a way to split the execution of marshaller and then merge it?

I can't use Stax or Sax.

Thanks in advance.

Fabio