how can i write criteria for nested datasource

data:[{
contactID:15,
contactEmail:"sdfsdfdsf",
account:{
accountID:2,
accountDetails:null,
accountPassword:"2222",
contact:[
{
contactID:14,
contactEmail:"sdfsdfsdf",
account:null,
contactTel:"sdfsdf",
contactAddress:"xcvxv"
},
null,
{
contactID:16,
contactEmail:"12212121212",
account:null,
contactTel:"121212121212",
contactAddress:"sdfdsfsdf"
}
],
accountRole:2,
accountUsername:"2"
},
contactTel:"sdfsdfds",
contactAddress:"dfvsdfdsf"
},


account ds

<DataSource
ID="account"
serverType="hibernate"
beanClassName="jpac.express.domain.Account"
schemaBean="jpac.express.domain.Account">
<field name="contact" type="contact" multiple="true" hidden="true" foreignKey="contact.accountID" />
<field name="accountDetails" type="accountDetails" hidden="true" foreignKey="accountDetails.accountID" />
<field name="accountRole">
<valueMap>
<value ID="1">test1</value>
<value ID="2">test2</value>
<value ID="3">test3</value>
</valueMap>
</field>
</DataSource>

contact ds
<DataSource
ID="contact"
serverType="hibernate"
beanClassName="jpac.express.domain.Contact"
schemaBean="jpac.express.domain.Contact">
</DataSource>

i want to select from contact ds where accountID is 2