<m:map>
<entry key="a"> <l:list> <a>a1</a> <a>a2</a> </l:list></entry>
<entry key="b"> <l:list> <b>b1</b> <b>b2</b> </l:list></entry>
</m:map>

class A { String property; }
class B { String property; }

<jb:bean beanId="inputValue" class="java.util.HashMap" createOnElement="StartElement">
        <jb:value property="prop"          data="StartElement/SomeValue/AnotherValue" />
    </jb:bean>


<g:groovy executeOnElement="StartElement">
         <g:imports>

        </g:imports>
        <g:script>
        <![CDATA[
                //code for setting the objects

        ]]>
        </g:script>
    </g:groovy>