You can manually modify the XPath for the repeating group in the mapping.xml. Change this:
<my:RepeatingGroup>my:myFieldsmy:group1/my:inventory_items/my:item</my:RepeatingGroup>
To this:
<my:RepeatingGroup>my:myFieldsmy:group1/my:inventory_items/my:item[my:approval='true']</my:RepeatingGroup>
Assuming your field is named "approval".... and I see that you say the value is "Yes" but it is boolean, which confuses me -- if your form saves yes or no in the XML, you'll need to use 'yes' instead of true.