Script assertion - iterate through Datasource properties?

XML:

<Results>
    <ResultSet fetchSize="0">
        <Row rowNumber="1">
            <PTD_POLICY_NUMBER>IF44514H7</PTD_POLICY_NUMBER>
            <PTD_DATE/>
            <PTD_ANIMAL_TYPE>A</PTD_ANIMAL_TYPE>
            <PTD_ANIMAL_BREED>18</PTD_ANIMAL_BREED>
            <PTD_ANIMAL_COUNT>1</PTD_ANIMAL_COUNT>
            <PTD_POLICYHOLDER_SSN>918179825</PTD_POLICYHOLDER_SSN>
            <PTD_REC_CREATE_DATE>20110912</PTD_REC_CREATE_DATE>
        </Row>
        <Row rowNumber="2">
            <PTD_POLICY_NUMBER>IF44514H7</PTD_POLICY_NUMBER>
            <PTD_DATE/>
            <PTD_ANIMAL_TYPE>B</PTD_ANIMAL_TYPE>
            <PTD_ANIMAL_BREED>05</PTD_ANIMAL_BREED>
            <PTD_ANIMAL_COUNT>1</PTD_ANIMAL_COUNT>
            <PTD_POLICYHOLDER_SSN>918179825</PTD_POLICYHOLDER_SSN>
            <PTD_REC_CREATE_DATE>20110912</PTD_REC_CREATE_DATE>
        </Row>
    </ResultSet>
</Results>

Groovy script below. As you can see, I'm expanding all of the Datasource properties that I will need for that particular assertion. If I wanted to check PTD_ANIMAL_BREED, I'd be expanding all of the Datasource properties named PTD_ANIMAL_BREED_x.

def pTD_ANIMAL_TYPE_0 = context.expand( '${DataSource#PTD_ANIMAL_TYPE_0}' )
def pTD_ANIMAL_TYPE_1 = context.expand( '${DataSource#PTD_ANIMAL_TYPE_1}' )
def expectedAnimalTypes = [pTD_ANIMAL_TYPE_0, pTD_ANIMAL_TYPE_1]
def responseAsXml = context.expand( '${JDBC Request#ResponseAsXml}' )
def results = new XmlSlurper().parseText(responseAsXml)
...