Yes, this is possible. When using the mapping tool to map your form fields to the SharePoint list, you can use relative paths to point to fields outside of the repeating node. So, for example, let's say the my:subcontractor node is at the root:
my:myFields/my:subcontrator
And you have a repeating group at
my:myFields/my:subcontrator/my:itemsContainerGroup/my:itemsRepeatingGroup
Your mapping tool would have the checkbox for "repeating data" checked and the repeating node would be this one above.
However, when mapping to a Sharepoint column for the subcontractor, you can type in the xpath manually, like this:
../../my:subcontractor
Hope that helps!